Material for organic electroluminescence device and organic electroluminescence device

ABSTRACT

A material for an organic electroluminescence device, includes: an organic material that is to be provided for a film formation of any of at least one organic layer included in the organic electroluminescence device, the organic material having a water content before the film formation, as measured by the Karl Fischer method, of 100 ppm or more and not more than 1,000 ppm.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a material for organicelectroluminescence device and an organic electroluminescence device(hereinafter also referred to as “device” or “organic EL device”). Theinvention relates to a technology capable of reducing a rate ofoccurrence of short-circuit device in the manufacture and enhancingmanufacturing yields and a technology capable of enhancing storagestability of the device.

2. Description of the Related Art

In recent years, in view of the fact that light emission with a highbrightness is obtainable through low-voltage driving, an organicelectroluminescence device has been actively researched and developed.In general, the organic electroluminescence device is constituted of anorganic layer including a light emitting layer and a pair of electrodesinterposing this light emitting layer therebetween, and energy of anexciton generated through recombination of an electron injected from acathode and a hole injected from an anode is utilized for the lightemission.

In the organic electroluminescence device, an improvement of efficiencyof the device is being advanced by using a phosphorescent material. Asthe phosphorescent material, there is known an iridium complex, aplatinum complex or the like, which is capable of undergoing blue, greenor red light emission. For example, US-A-2007/0190359 andUS-A-2008/0297033 disclose an iridium complex of a ligand having acondensed ring structure.

The organic electroluminescence device is required to have highdurability such that it endures long-term light emission. However, it iswell known that penetration of moisture into the device generates a darkspot, thereby lowering the durability. It may be considered that this iscaused due to the fact that a water molecule accelerates chemicaldecomposition of a material, or accelerates separation between anorganic layer and an electrode interface.

In response to this, there have been made various countermeasures forthe purpose of preventing a lowering of durability to be caused due tothe penetration of moisture; and there have been disclosed a reductionof the water content in a thin film due to dehydration after filmformation (see, for example, WO 01/058221); protection from thepenetration of moisture by a sealing structure (see, for example,JP-A-2007-87620, JP-A-2006-294534 and JP-A-2006-278067); utilization ofa moisture absorbing material or a moisture capturing material (see, forexample, JP-A-2006-66366 and JP-A-2006-210095); and the like.

Also, it is disclosed that a heat treatment is carried out in vacuoduring the film formation, thereby removing moisture (see, for example,JP-A-2003-313654).

Also, it is disclosed that in the case where a layer is formed by a wetfilm formation method, moisture contained in a composition for organicelectroluminescence device is decreased as far as possible such that themoisture does not remain in the film after drying, thereby suppressing alowering of characteristics of the device (see, for example,JP-A-2009-102656).

On the other hand, it is well known that inclusion of fine dusts into adevice causes an electrical short circuit of the device, resulting in alowering of manufacturing yields. As to a method of preventing the shortcircuit to be caused due to the inclusion of fine dusts, it is proposedthat a flattened layer is provided between an anode layer and an organiclayer (see, for example, JP-A-11-224781). However, according to thismethod, occurrence of a defective of the device to be caused due to thefine dusts in the organic layer cannot be avoided.

Also, it is proposed that a relative humidity at the time of filmformation by a wet film formation method is regulated to 0.01 ppm ormore, thereby suppressing the generation of static electricity duringthe film formation (see, for example, JP-A-2009-146691).

Also, it is proposed that a relative humidity in a pre-treatment step ofvapor deposition is regulated to 0.01 ppm or more, thereby making iteasy to control the circumstances constant and making it possible tostably manufacture a device (see, for example, JP-A-2008-192433).

SUMMARY OF THE INVENTION

An object of the invention is to provide a material for organicelectroluminescence device capable of obtaining an organicelectroluminescence device with excellent light emitting characteristicsand capable of reducing the number of short-circuit devices; and anorganic electroluminescence device using the subject material fororganic electroluminescence device.

Also, another object of the invention is to provide a composition usefulfor organic electroluminescence devices and a light emitting layer.Then, a still another object of the invention is to provide a lightemission apparatus and an illumination apparatus each of which includesan organic electroluminescence device.

As disclosed in WO 01/058221 and JP-A-2009-102656 and the like, it isknown that the inclusion of even a slight amount of moisture is notpreferable for the durability of the device. In an embodiment accordingto the invention, in which a material containing moisture in an amountwithin a specified range is used for the material for organicelectroluminescence device, in the light of its technical knowledge, itcould not be expected that such an embodiment is effective for themanufacture of a device or an enhancement of characteristics.

However, as a result of extensive and intensive investigations made bythe present inventor, it has been found that by using, as an organicmaterial to be provided for film formation of any one of layers of atleast one organic layer included in an organic electroluminescencedevice, a material for organic electroluminescence device having a watercontent before film formation, as measured by the Karl Fischer method,of 100 ppm or more and not more than 1,000 ppm, in an organicelectroluminescence device including a layer obtained by film formationof such a material, a probability of occurrence of short-circuit devicecan be lowered, thereby enhancing the yields without lowering drivingdurability. The foregoing water content refers to a water content beforefilm formation. Also, at the same time, it has been found that the useof such a material is also effective for suppressing occurrence ofcloudiness of the device at the time of device storage. Thoughmechanisms of these effects have not been elucidated yet, it may bepresumed that electrification is suppressed by adsorbed water on thesurface of a solid so that attachment of fine dusts to be caused due tothe electrification is suppressed. As a result, it may be consideredthat the inclusion of fine dusts into the device can be suppressed,thereby bringing an effect for reducing an short-circuit device or anenhancement of storage stability.

It may be considered that the water content of the iridium complexessynthesized by the methods disclosed in US-A-2007/0190359 andUS-A-2008/0297033 is less than 5 ppm.

That is, the invention has been achieved by the following means.

[1] A material for an organic electroluminescence device, comprising:

an organic material that is to be provided for a film formation of anyof at least one organic layer included in the organicelectroluminescence device, the organic material having a water contentbefore the film formation, as measured by the Karl Fischer method, of100 ppm or more and not more than 1,000 ppm.

[2] The material for an organic electroluminescence as described in [1]above,

wherein the organic material is an organometallic compound having acarbon-metal bond.

[3] The material for an organic electroluminescence device as describedin [2] above,

wherein the organometallic compound having a carbon-metal bond is aniridium complex material represented by the following formula (E-1):

in the formula (E-1), each of Z¹ and Z² independently represents acarbon atom or a nitrogen atom;

A represents an atomic group for forming a 5- or 6-membered aromaticring together with Z¹ and N;

B represents an atomic group for forming a 5- or 6-membered aromaticring together with Z² and C;

though each of a line connecting Z¹ and N, a line connecting Z¹ and theatomic group A, a line connecting N and the atomic group A, a lineconnecting Z² and C, a line connecting Z² and the atomic group B and aline connecting C and the atomic group B is expressed by a single line,each may be either a single bond or a double bond irrespective of abonding species;

X—Y represents a monoanionic bidentate ligand represented by thefollowing formula (I-1), (I-2) or (I-3); and

n represents an integer of from 1 to 3:

in the formula (I-1), each of Rx and Rz independently represents analkyl group, a perfluoroalkyl group or an aryl group; and

Ry represents a hydrogen atom, an alkyl group, a perfluoroalkyl group oran aryl group,

in the formula (I-2), each of Ri¹ to Ri⁴ independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and

adjacent substituents among Ri¹ to Ri⁴ may be connected to each other,and

in the formula (I-3), each of Ri⁵ to Ri¹² independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and

adjacent substituents among Ri⁵ to Ri⁸, adjacent substituents among Ri⁹to Ri¹², and Ri⁸ and Ri⁹ may be each connected to each other.

[4] The material for an organic electroluminescence device as describedin [3] above,

wherein the iridium complex material represented by the formula (E-1) isrepresented by the following formula (E-2):

in the formula (E-2), each of A¹ to A⁸ independently represents anitrogen atom or C—R;

R represents a hydrogen atom, an alkyl group, an aryl group, an aromaticheterocyclic group, a cyano group, a silyl group, an amino group or afluorine atom;

X—Y is synonymous with X—Y in the formula (E-1); and

n represents an integer of from 1 to 3.

[5] The material for an organic electroluminescence device as describedin [3] above,

wherein the iridium complex material represented by the formula (E-1) isrepresented by the following formula (E-3):

in the formula (E-3), each of A⁹ to A¹¹ and A¹³ to A¹⁶ independentlyrepresents C—R, N or N—R′;

A¹² represents a carbon atom or a nitrogen atom;

R represents a hydrogen atom, an alkyl group, an aryl group, an aromaticheterocyclic group, a cyano group, a silyl group, an amino group or afluorine atom;

R′ represents a hydrogen atom, an alkyl group or an aryl group;

X—Y is synonymous with X—Y in the formula (E-1); and

n represents an integer of from 1 to 3.

[6] The material for an organic electroluminescence device as describedin [5] above,

wherein the iridium complex material represented by the formula (E-3) isrepresented by the following formula (E-4):

in the formula (E-4), each of R_(1a) to R_(1i) independently representsa hydrogen atom, an alkyl group, an aryl group, an aromatic heterocyclicgroup, a cyano group, a silyl group, an amino group or a fluorine atom;

X—Y is synonymous with X—Y in the formula (E-1); and

n represents an integer of from 1 to 3.

[7] The material for an organic electroluminescence device as describedin [6] above,

wherein in the formula (E-4), n is 3.

[8] The material for an organic electroluminescence device as describedin [2] above,

wherein the organometallic compound having a carbon-metal bond is aniridium complex material represented by the following formula (PQ-1):

in the formula (PQ-1), each of R₁ to R₁₀ independently represents ahydrogen atom, an alkyl group, an aryl group, an aromatic heterocyclicgroup, a cyano group, a silyl group, an amino group or a fluorine atom;

R₁ to R₁₀ may be bonded to each other to form a ring, if possible;

X^(P)—Y^(P) represents a monoanionic bidentate ligand represented by thefollowing formula (I-1), (I-2) or (I-3); and

n represents an integer of from 1 to 3:

in the formula (I-1), each of Rx and Rz independently represents analkyl group, a perfluoroalkyl group or an aryl group; and

Ry represents a hydrogen atom, an alkyl group, a perfluoroalkyl group oran aryl group,

in the formula (I-2), each of Ri¹ to Ri⁴ independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and

adjacent substituents among Ri¹ to Ri⁴ may be connected to each other,and

in the formula (I-3), each of Ri⁵ to Ri¹² independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and

adjacent substituents among Ri⁵ to Ri⁸, adjacent substituents among Ri⁹to Ri¹², and Ri⁸ and Ri⁹ may be each connected to each other.

[9] The material for an organic electroluminescence device as describedin [8] above,

wherein in the iridium complex represented by the formula (PQ-1), n is2; and

the monoanionic bidentate ligand represented by X^(P)—Y^(P) is a ligandrepresented by the following formula L:

in the formula L, each of R^(L1) and R^(L2) independently represents analkyl group having from 1 to 5 carbon atoms or a phenyl group which mayhave a substituent selected from the substituent group T2 consisting ofan alkyl group having from 1 to 6 carbon atoms, an alkenyl group havingfrom 2 to 6 carbon atoms, a phenyl group, an aromatic heterocyclic grouphaving from 5 to 10 carbon atoms, an alkoxy group having from 1 to 4carbon atoms, a phenoxy group, a fluorine atom, a silyl group, an aminogroup, a cyano group and a group composed of a combination of thesegroups; and

plural substituents selected from the substituent group T2 may beconnected to each other to form an aromatic hydrocarbon ring.

[10] A light emitting layer, which is prepared using the material for anorganic electroluminescence device as described in any one of [1] to [9]above.

[11] The light emitting layer as described in [10] above, furthercomprising:

a compound represented by the following formula (4-1) or (4-2):

in the formulae (4-1) and (4-2), each of d and e independentlyrepresents an integer of from 0 to 3, and at least one of d and e is 1or more;

f represents an integer of from 1 to 4;

R′₈ represents an alkyl group, an aryl group, a heteroaryl group, afluorine atom, a cyano group, an alkoxy group, an aryloxy group, anamino group or a silyl group, and when plural R′₈s are present, each R′₈may be the same as or different from every other R′₈; and

at least one of R′₈s represents a group represented by the followingformula (5):

in the formula (5), each of R′₉s independently represents an alkylgroup, an aryl group, a heteroaryl group, a fluorine atom, a cyanogroup, an alkoxy group, an aryloxy group, an amino group or a silylgroup; and

g represents an integer of from 0 to 8.

[12] A composition, comprising:

the material for an organic electroluminescence device as described inany one of [1] to [9] above.

[13] The composition as described in [12] above, further comprising:

a compound represented by the following formula (4-1) or (4-2):

in the formulae (4-1) and (4-2), each of d and e independentlyrepresents an integer of from 0 to 3, and at least one of d and e is 1or more;

f represents an integer of from 1 to 4;

R′₈ represents an alkyl group, an aryl group, a heteroaryl group, afluorine atom, a cyano group, an alkoxy group, an aryloxy group, anamino group or a silyl group, and when plural R′₈s are present, each R′₈may be the same as or different from every other R′₈; and

at least one of R′₈s represents a group represented by the followingformula (5):

in the formula (5), each of R′₉s independently represents an alkylgroup, an aryl group, a heteroaryl group, a fluorine atom, a cyanogroup, an alkoxy group, an aryloxy group, an amino group or a silylgroup; and

g represents an integer of from 0 to 8.

[14] An organic electroluminescence device, comprising:

a substrate having thereon a pair of electrodes; and

at least one organic layer including a light emitting layer between thepair of electrodes,

wherein the material for an organic electroluminescence device asdescribed in any one of [1] to [9] above is used in at least one layerof the at least one organic layer.

[15] A method for manufacturing an organic electroluminescence device,comprising:

using the material for an organic electroluminescence device asdescribed in any one of [1] to [9] above.

[16] A method for reducing a rate of occurrence of short-circuit device,comprising:

using the material for an organic electroluminescence device asdescribed in any one of [1] to [9] above.

[17] A display apparatus, comprising:

the material for an organic electroluminescence device as described inany one of [1] to [9] above.

[18] An illumination apparatus, comprising:

the material for an organic electroluminescence device as described inany one of [1] to [9] above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view showing an example of a layerconfiguration of an organic electroluminescence device according to theinvention;

FIG. 2 is a diagrammatic view showing an example of a light emissionapparatus according to the invention;

FIG. 3 is a diagrammatic view showing an example of an illuminationapparatus according to the invention; and

FIG. 4 is a graph showing a relation between a water content (ppm) of amaterial for organic electroluminescence device according to theinvention and the number of short-circuit devices (%) in the obtaineddevices.

DETAILED DESCRIPTION OF THE INVENTION

In the invention, a substituent group A and a substituent group B aredefined as follows.

(Substituent Group A)

Examples of the substituent group A include an alkyl group (preferablyan alkyl group having from 1 to 30 carbon atoms, more preferably analkyl group having from 1 to 20 carbon atoms, and especially preferablyan alkyl group having from 1 to 10 carbon atoms; for example, methyl,ethyl, isopropyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl,cyclopropyl, cyclopentyl, cyclohexyl, etc.), a perfluoroalkyl group(preferably a perfluoroalkyl group having from 1 to 10 carbon atoms,more preferably a perfluoroalkyl group having from 1 to 5 carbon atoms,and especially preferably a perfluoroalkyl group having from 1 to 3carbon atoms; for example, trifluoromethyl, pentafluoroethyl, etc.), analkenyl group (preferably an alkenyl group having from 2 to 30 carbonatoms, more preferably an alkenyl group having from 2 to 20 carbonatoms, and especially preferably an alkenyl group having from 2 to 10carbon atoms; for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.),an alkynyl group (preferably an alkynyl group having from 2 to 30 carbonatoms, more preferably an alkynyl group having from 2 to 20 carbonatoms, and especially preferably an alkynyl group having from 2 to 10carbon atoms; for example, propargyl, 3-pentynyl, etc.), an aryl group(preferably an aryl group having from 6 to 30 carbon atoms, morepreferably an aryl group having from 6 to 20 carbon atoms, andespecially preferably from 6 to 12 carbon atoms; for example, phenyl,p-methylphenyl, naphthyl, anthranyl, etc.), an amino group (preferablyan amino group having from 0 to 30 carbon atoms, more preferably anamino group having from 0 to 20 carbon atoms, and especially preferablyan amino group having from 0 to 10 carbon atoms; for example, amino,methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino,ditolylamino, etc.), an alkoxy group (preferably an alkoxy group havingfrom 1 to 30 carbon atoms, more preferably an alkoxy group having from 1to 20 carbon atoms, and especially preferably an alkoxy group havingfrom 1 to 10 carbon atoms; for example, methoxy, ethoxy, butoxy,2-ethylhexyloxy, etc.), an aryloxy group (preferably an aryloxy grouphaving from 6 to 30 carbon atoms, an aryloxy group having from 6 to 20carbon atoms, and especially preferably an aryloxy group having from 6to 12 carbon atoms; for example, phenyloxy, 1-naphthyloxy,2-naphthyloxy, etc.), a heterocyclic oxy group (preferably aheterocyclic oxy group having from 1 to 30 carbon atoms, more preferablya heterocyclic oxy group having from 1 to 20 carbon atoms, andespecially preferably a heterocyclic oxy group having from 1 to 12carbon atoms; for example, pyridyloxy, pyrazyloxy, pyrimidyloxy,quinolyloxy, etc.), an acyl group (preferably an acyl group having from1 to 30 carbon atoms, more preferably an acyl group having from 1 to 20carbon atoms, and especially preferably an acyl group having from 1 to12 carbon atoms; for example, acetyl, benzoyl, formyl, pivaloyl, etc.),an alkoxycarbonyl group (preferably an alkoxycarbonyl group having from2 to 30 carbon atoms, more preferably an alkoxycarbonyl group havingfrom 2 to 20 carbon atoms, and especially preferably an alkoxycarbonylgroup having from 2 to 12 carbon atoms; for example, methoxycarbonyl,ethoxycarbonyl, etc.), an aryloxycarbonyl group (preferably anaryloxycarbonyl group having from 7 to 30 carbon atoms, more preferablyan aryloxycarbonyl group having from 7 to 20 carbon atoms, andespecially preferably an aryloxycarbonyl group having from 7 to 12carbon atoms; for example, phenyloxycarbonyl, etc.), an acyloxy group(preferably an acyloxy group having from 2 to 30 carbon atoms, morepreferably an acyloxy group having from 2 to 20 carbon atoms, andespecially preferably an acyloxy group having from 2 to 10 carbon atoms;for example, acetoxy, benzoyloxy, etc.), an acylamino group (preferablyan acylamino group having from 2 to 30 carbon atoms, more preferably anacylamino group having from 2 to 20 carbon atoms, and especiallypreferably an acylamino group having from 2 to 10 carbon atoms; forexample, acetylamino, benzoylamino, etc.), an alkoxycarbonylamino group(preferably an alkoxycarbonylamino group having from 2 to 30 carbonatoms, more preferably an alkoxycarbonylamino group having from 2 to 20carbon atoms, and especially preferably an alkoxycarbonylamino grouphaving from 2 to 12 carbon atoms; for example, methoxycarbonylamino,etc.), an aryloxycarbonylamino group (preferably an aryloxycarbonylaminogroup having from 7 to 30 carbon atoms, more preferably anaryloxycarbonylamino group having from 7 to 20 carbon atoms, andespecially preferably an aryloxycarbonylamino group having from 7 to 12carbon atoms; for example, phenyloxycarbonylamino, etc.), asulfonylamino group (preferably a sulfonylamino group having from 1 to30 carbon atoms, more preferably a sulfonylamino group having from 1 to20 carbon atoms, and especially preferably a sulfonylamino group havingfrom 1 to 12 carbon atoms; for example, methanesulfonylamino,benzenesulfonylamino, etc.), a sulfamoyl group (preferably a sulfamoylgroup having from 0 to 30 carbon atoms, more preferably a sulfamoylgroup having from 0 to 20 carbon atoms, and especially preferably asulfamoyl group having from 0 to 12 carbon atoms; for example,sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc.), acarbamoyl group (preferably a carbamoyl group having from 1 to 30 carbonatoms, more preferably a carbamoyl group having from 1 to 20 carbonatoms, and especially preferably a carbamoyl group having from 1 to 12carbon atoms; for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl,phenylcarbamoyl, etc.), an alkylthio group (preferably an alkylthiogroup having from 1 to 30 carbon atoms, more preferably an alkylthiogroup having from 1 to 20 carbon atoms, and especially preferably analkylthio group having from 1 to 12 carbon atoms; for example,methylthio, ethylthio, etc.), an arylthio group (preferably an arylthiogroup having from 6 to 30 carbon atoms, more preferably an arylthiogroup having from 6 to 20 carbon atoms, and especially preferably anarylthio group having from 6 to 12 carbon atoms; for example,phenylthio, etc.), a heterocyclic thio group (preferably a heterocyclicthio group having from 1 to 30 carbon atoms, more preferably aheterocyclic thio group having from 1 to 20 carbon atoms, and especiallypreferably a heterocyclic thio group having from 1 to 12 carbon atoms;for example, pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio,2-benzothiazolylthio, etc.), a sulfonyl group (preferably a sulfonylgroup having from 1 to 30 carbon atoms, more preferably a sulfonyl grouphaving from 1 to 20 carbon atoms, and especially preferably a sulfonylgroup having from 1 to 12 carbon atoms; for example, mesyl, tosyl,etc.), a sulfinyl group (preferably a sulfinyl group having from 1 to 30carbon atoms, more preferably a sulfinyl group having from 1 to 20carbon atoms, and especially preferably a sulfinyl group having from 1to 12 carbon atoms; for example, methanesulfinyl, benzenesulfinyl,etc.), a ureido group (preferably a ureido group having from 1 to 30carbon atoms, more preferably a ureido group having from 1 to 20 carbonatoms, and especially preferably a ureido group having from 1 to 12carbon atoms; for example, ureido, methylureido, phenylureido, etc.), aphosphoric acid amide group (preferably a phosphoric acid amide grouphaving from 1 to 30 carbon atoms, more preferably a phosphoric acidamide group having from 1 to 20 carbon atoms, and especially preferablya phosphoric acid amide group having from 1 to 12 carbon atoms; forexample, diethylphosphoric acid amide, phenylphosphoric acid amide,etc.), a hydroxyl group, a mercapto group, a halogen atom (for example,a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), acyano group, a sulfo group, a carboxyl group, a nitro group, ahydroxamic acid group, a sulfino group, a hydrazino group, an iminogroup, a heterocyclic group (inclusive of an aromatic heterocyclicgroup) (preferably a heterocyclic group having from 1 to 30 carbonatoms, and more preferably a heterocyclic group having from 1 to 12carbon atoms; the hetero atom as referred to herein means an atom otherthan a carbon atom or a hydrogen atom, examples thereof include anitrogen atom, an oxygen atom, a sulfur atom, phosphorus atom, a siliconatom, a selenium atom and a tellurium atom, and of these, an oxygenatom, a nitrogen atom and a sulfur atom are preferable, with an oxygenatom and a nitrogen atom being more preferable; and specific examples ofthe heterocyclic group include pyridyl, pyrazinyl, pyrimidyl,pyridazinyl, pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl,thiazolyl, isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl,selenophenyl, tellurophenyl, piperidyl, piperidino, morpholino,pyrrolidyl, pyrrolidino, benzoxazolyl, benzimidazolyl, benzothiazolyl,carbazolyl, azepinyl, silolyl, etc.), a silyl group (preferably a silylgroup having from 3 to 40 carbon atoms, more preferably a silyl grouphaving from 3 to 30 carbon atoms, and especially preferably a silylgroup having from 3 to 24 carbon atoms; for example, trimethylsilyl,triphenylsilyl, etc.), a silyloxy group (preferably a silyloxy grouphaving from 3 to 40 carbon atoms, more preferably a silyloxy grouphaving from 3 to 30 carbon atoms, and especially preferably a silyloxygroup having from 3 to 24 carbon atoms; for example, trimethylsilyloxy,triphenylsilyloxy, etc.) and a phosphoryl group (for example,diphenylphosphoryl, dimethylphosphoryl, etc.). Such a substituent may befurther substituted. As the further substituent, those describedpreviously in the substituent group A can be exemplified.

(Substituent Group B)

Examples of the substituent group B include an alkyl group (preferablyan alkyl group having from 1 to 30 carbon atoms, more preferably analkyl group having from 1 to 20 carbon atoms, and especially preferablyan alkyl group having from 1 to 10 carbon atoms; for example, methyl,ethyl, isopropyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl,cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group(preferably an alkenyl group having from 2 to 30 carbon atoms, morepreferably an alkenyl group having from 2 to 20 carbon atoms, andespecially preferably an alkenyl group having from 2 to 10 carbon atoms;for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynylgroup (preferably an alkynyl group having from 2 to 30 carbon atoms,more preferably an alkynyl group having from 2 to 20 carbon atoms, andespecially preferably an alkynyl group having from 2 to 10 carbon atoms;for example, propargyl, 3-pentynyl, etc.), an aryl group (preferably anaryl group having from 6 to 30 carbon atoms, more preferably an arylgroup having from 6 to 20 carbon atoms, and especially preferably from 6to 12 carbon atoms; for example, phenyl, p-methylphenyl, naphthyl,anthranyl, etc.), a cyano group and a heterocyclic group (inclusive ofan aromatic heterocyclic group) (preferably a heterocyclic group havingfrom 1 to 30 carbon atoms, and more preferably a heterocyclic grouphaving from 1 to 12 carbon atoms; examples of the hetero atom include anitrogen atom, an oxygen atom, a sulfur atom, phosphorus atom, a siliconatom, a selenium atom and a tellurium atom; and specific examples of theheterocyclic group include pyridyl, pyrazinyl, pyrimidyl, pyridazinyl,pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, thiazolyl,isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl,tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl,pyrrolidino, benzoxazolyl, benzimidazolyl, benzothiazolyl, carbazolyl,azepinyl, silolyl, etc.). Such a substituent may be further substituted.As the further substituent, those described previously in thesubstituent group A can be exemplified.

The material for organic electroluminescence device of the invention isan organic material to be provided for film formation of any one oflayers of at least one organic layer included in the organicelectroluminescence device; and this material is a material for organicelectroluminescence device having a water content of a sample (organicmaterial) before film formation, as measured by the Karl Fischer method,in other words, a water content obtained by measuring moisture which hasbeen heated and vaporized from a sample (organic material) in a solidstate before film formation by vapor deposition or the like, by the KarlFischer method, is 100 ppm or more and not more than 1,000 ppm (namely,the water content in 1 kg of the sample (organic material) before filmformation is 100 mg or more and not more than 1,000 mg).

By preparing an organic electroluminescence device using the materialhaving a water content falling within the foregoing range, it ispossible to reduce a probability of occurrence of short-circuit device,thereby enhancing the yields without lowering durability. Also, it ispossible to suppress crystallization of a thin film in the device,thereby enhancing storage durability. It may be considered that this iscaused due to the fact that by incorporating a trace amount of moisture,not only dust collection due to electrification of the material can beprevented, but inclusion of fine dusts into the device prepared usingthis material can be prevented.

Examples of the Karl Fischer method include a method in which by using aKarl Fischer trace moisture meter (CA-200, manufactured by MitsubishiChemical Analytech Co., Ltd.), a material for organicelectroluminescence device is heated to 140° C. by a water vaporizer(VA-200, manufactured by Mitsubishi Chemical Analytech Co., Ltd.), andvaporized moisture is sent to a titration cell with dry N₂ at a flowrate of 250 mL/min, thereby measuring a water content of the material.

When the term “water content” is simply referred to in this application,it means a water content measured by the Karl Fischer method.

The material for organic electroluminescence device of the invention ispreferably used for film formation of a light emitting layer, and morepreferably used for film formation of a light emitting layer as a lightemitting material.

The material for organic electroluminescence device having a watercontent before film formation of 100 ppm or more and not more than 1,000ppm according to the invention is preferably an organometallic compoundhaving a carbon-metal bond.

From the viewpoint that larger effects are brought, it is preferablethat the organometallic compound having a carbon-metal bond is aniridium complex material represented by the following formula (E-1).

The formula (E-1) is described.

In the formula (E-1), each of Z¹ and Z² independently represents acarbon atom or a nitrogen atom; A represents an atomic group for forminga 5- to 6-membered aromatic ring together with Z¹ and N; B represents anatomic group for forming a 5- to 6-membered aromatic ring together withZ² and C; though each of a line connecting Z¹ and N, a line connectingZ¹ and the atomic group A, a line connecting N and the atomic group A, aline connecting Z² and C, a line connecting Z² and the atomic group Band a line connecting C and the atomic group B is expressed by a singleline, each may be either a single bond or a double bond irrespective ofa bonding species; X—Y represents a monoanionic bidentate ligand; and nrepresents an integer of from 1 to 3.

n represents an integer of from 1 to 3. n is preferably 2 or 3, and mostpreferably 3.

Each of Z¹ and Z² independently represents a carbon atom or a nitrogenatom. For a reason that a device with a high external quantum efficiencyis obtained, each of Z¹ and Z² is preferably a carbon atom.

A represents an atomic group for forming a 5- to 6-membered aromaticring together with Z¹ and N. Examples of the 5- to 6-membered aromaticring containing the atomic group A, Z¹ and N include a pyridine ring, apyrimidine ring, a pyrazine ring, a triazine ring, an imidazole ring, apyrazole ring, an oxazole ring, a thiazole ring, a triazole ring, anoxadiazole ring and a thiadiazole ring. Such a ring may form a condensedring together with other ring.

From the viewpoints of stability of the complex, control of lightemission wavelength and light emission quantum yield, the 5- to6-membered aromatic ring formed by the atomic group A, Z¹ and N ispreferably a pyridine ring, a pyrazine ring, an imidazole ring or apyrazole ring; more preferably a pyridine ring, an imidazole ring or apyrazole ring; and further preferably a pyridine ring or an imidazolering.

The 5- to 6-membered aromatic ring formed by the atomic group A, Z¹ andN may have a substituent.

As the substituent which can be substituted on the carbon atom in the 5-to 6-membered aromatic ring formed by the atomic group A, Z¹ and N,those described previously in the substituent group A can beexemplified.

The substituent which can be substituted on the carbon atom ispreferably an alkyl group, a perfluoroalkyl group, an aryl group, anaromatic heterocyclic group, a dialkylamino group, a diarylamino group,an alkoxy group, a cyano group, a fluorine atom or a cycloalkyl group,and more preferably an alkyl group or an aryl group.

Though the substituent which can be substituted on the carbon atom inthe 5- to 6-membered aromatic ring formed by the atomic group A, Z¹ andN is properly selected for the purpose of controlling the light emissionwavelength or potential, in the case of making the wavelength short, thesubstituent is preferably an electron donating group, a fluorine atom oran aromatic ring group, and for example, an alkyl group, a dialkylaminogroup, an alkoxy group, a fluorine atom, an aryl group, an aromaticheterocyclic group and the like are selected. Also, in the case ofmaking the wavelength long, the substituent is preferably an electronwithdrawing group, and for example, a cyano group, a perfluoroalkylgroup and the like are selected.

At least two of these substituents may be bonded to each other to form aring; and examples of the ring to be formed include a benzene ring, apyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, animidazole ring, an oxazole ring, a thiazole ring, a pyrazole ring, athiophene ring and a furan ring, with a benzene ring, a pyridine ring, apyrazine ring, a pyridazine ring, a pyrimidine ring, an imidazole ringand a pyrazole ring being preferable.

Also, such a substituent may further have a substituent. As thesubstituent, those described previously in the substituent group A canbe exemplified. The substituent is preferably an alkyl group, aperfluoroalkyl group, an aryl group, an aromatic heterocyclic group, adialkylamino group, a diarylamino group, an alkoxy group, a cyano group,a fluorine atom or a cycloalkyl group; more preferably an alkyl group,an aryl group, a cyano group, a fluorine atom or a cycloalkyl group; andfurther preferably an alkyl group, a cyano group or a fluorine atom.

As the substituent which can be substituted on the nitrogen atom in the5- to 6-membered aromatic ring formed by the atomic group A, Z¹ and N,those described previously in the substituent group B can beexemplified.

The substituent which can be substituted on the nitrogen atom in the 5-to 6-membered aromatic ring formed by the atomic group A, Z¹ and N ispreferably an alkyl group, an aryl group or an aromatic heterocyclicgroup, and from the viewpoint of stability of the complex, thesubstituent is preferably an alkyl group or an aryl group.

Though the substituent which can be substituted on the nitrogen atom inthe 5- to 6-membered aromatic ring formed by the atomic group A, Z¹ andN is properly selected for the purpose of controlling the light emissionwavelength or potential, in the case of making the wavelength short, thesubstituent is preferably an electron donating group, a fluorine atom oran aromatic ring group, and for example, an alkyl group, a fluorineatom, an aryl group, an aromatic heterocyclic group and the like areselected. Also, in the case of making the wavelength long, thesubstituent is preferably an electron withdrawing group, and forexample, a cyano group and the like are selected.

The foregoing substituents may be connected to each other to form acondensed ring; and examples of the ring to be formed include a benzenering, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidinering, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazolering, a thiophene ring and a furan ring.

Also, such a substituent may further have a substituent. As thesubstituent, those described previously in the substituent group A canbe exemplified. The substituent is preferably an alkyl group, aperfluoroalkyl group, an aryl group, an aromatic heterocyclic group, adialkylamino group, a diarylamino group, an alkoxy group, a cyano group,a fluorine atom or a cycloalkyl group; more preferably an alkyl group,an aryl group, a cyano group, a fluorine atom or a cycloalkyl group; andfurther preferably an alkyl group, a cyano group or a fluorine atom.

B represents an atomic group for forming a 5- to 6-membered aromaticring together with Z² and C. Examples of the 5- to 6-membered aromaticring formed by the atomic group B, Z² and C include a benzene ring, apyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, atriazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, athiazole ring, a triazole ring, an oxadiazole ring, a thiadiazole ring,a thiophene ring and a furan ring. From the viewpoints of stability ofthe complex, control of light emission wavelength and light emissionquantum yield, the 5- to 6-membered aromatic ring formed by the atomicgroup B, Z² and C is preferably a benzene ring, a pyridine ring, apyrazine ring, an imidazole ring, a pyrazole ring or a thiophene ring;more preferably a benzene ring, a pyridine ring or a pyrazole ring; andfurther preferably a benzene ring or a pyridine ring.

The 5- to 6-membered aromatic ring formed by the atomic group B, Z² andC may have a substituent.

As the substituent which can be substituted on the carbon atom in the 5-to 6-membered aromatic ring formed by the atomic group B, Z² and C,those described previously in the substituent group A can beexemplified.

The substituent which can be substituted on the carbon atom ispreferably an alkyl group, a perfluoroalkyl group, an aryl group, anaromatic heterocyclic group, a dialkylamino group, a diarylamino group,an alkoxy group, a cyano group or a fluorine atom.

Though the substituent is properly selected for the purpose ofcontrolling the light emission wavelength or potential, in the case ofmaking the wavelength long, the substituent is preferably an electrondonating group or an aromatic ring group, and for example, an alkylgroup, a dialkylamino group, an alkoxy group, an aryl group, an aromaticheterocyclic group and the like are selected. Also, in the case ofmaking the wavelength short, the substituent is preferably an electronwithdrawing group, and for example, a fluorine atom, a cyano group, aperfluoroalkyl group and the like are selected.

As the substituent which can be substituted on the nitrogen atom in the5- to 6-membered aromatic ring formed by the atomic group B, Z² and C,those described previously in the substituent group B can beexemplified.

The substituent which can be substituted on the nitrogen atom ispreferably an alkyl group, an aryl group or an aromatic heterocyclicgroup, and from the viewpoint of stability of the complex, thesubstituent is preferably an alkyl group or an aryl group.

Though the substituent which can be substituted on the nitrogen atom inthe 5- to 6-membered aromatic ring formed by the atomic group B, Z² andC is properly selected for the purpose of controlling the light emissionwavelength or potential, in the case of making the wavelength short, thesubstituent is preferably an electron donating group, a fluorine atom oran aromatic ring group, and for example, an alkyl group, a fluorineatom, an aryl group, an aromatic heterocyclic group and the like areselected. Also, in the case of making the wavelength long, thesubstituent is preferably an electron withdrawing group, and forexample, a cyano group and the like are selected.

The foregoing substituents may be connected to each other to form aring; and examples of the ring to be formed include a benzene ring, apyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, animidazole ring, an oxazole ring, a thiazole ring, a pyrazole ring, athiophene ring, a furan ring and a cyclopentadiene ring (for example, anembodiment as in Illustrative Compound 59).

Also, such a substituent may further have a substituent. As thesubstituent, those described previously in the substituent group A canbe exemplified. The substituent is preferably an alkyl group, aperfluoroalkyl group, an aryl group, an aromatic heterocyclic group, adialkylamino group, a diarylamino group, an alkoxy group, a cyano group,a fluorine atom or a cycloalkyl group; more preferably an alkyl group,an aryl group, a cyano group, a fluorine atom or a cycloalkyl group; andfurther preferably an alkyl group, a cyano group or a fluorine atom.

The 5- to 6-membered aromatic ring formed by the atomic group A, Z¹ andN and the 5- to 6-membered aromatic ring formed by the atomic group B,Z² and C may be further bonded to each other via a connecting group, toform a ring.

In the formula (E-1), X—Y represents a monoanionic bidentate ligand. Itmay be considered that such a ligand does not directly contribute tolight emitting characteristics but is able to control the light emittingcharacteristics of a molecule. The monoanionic bidentate ligand which isused in the light emitting material can be selected from those which areknown in the art. Examples of such a monoanionic bidentate ligandinclude ligands disclosed on pages 89 to 90 of Lamansky, et al., WO02/15645, but it should not be construed that the invention is limitedthereto.

It is preferable that X—Y represents a monoanionic bidentate ligandrepresented by the following formula (I-1), (I-2) or (I-3).

In the formula (I-1), each of Rx and Rz independently represents analkyl group, a perfluoroalkyl group or an aryl group; and Ry representsa hydrogen atom, an alkyl group, a perfluoroalkyl group or an arylgroup.

In the formula (I-2), each of Ri¹ to Ri⁴ independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and adjacentsubstituents among Ri¹ to Ri⁴ may be connected to each other.

In the formula (I-3), each of Ri⁵ to Ri¹² independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and adjacentsubstituents among Ri⁵ to Ri⁸, adjacent substituents among Ri⁹ to Ri¹²,and Ri⁸ and Ri⁹ may be each connected to each other.

In the formulae (I-1), (I-2) and (I-3), the monoanionic bidentate ligandis bonded to iridium at the atom marked with “*”.

In the formula (I-1), each of Rx and Rz independently represents analkyl group, a perfluoroalkyl group or an aryl group. Each of Rx and Rzis preferably an alkyl group having from 1 to 5 carbon atoms, atrifluoromethyl group or a phenyl group which may have a substituentselected from the following substituent group T (also referred to as“substituent T”). Plural substituents Ts may be connected to each other.In the invention, the substituent group T is defined as follows.

(Substituent Group T)

An alkyl group having a from 1 to 6 carbon atoms, a phenyl group, anaromatic heterocyclic group having from 5 to 10 carbon atoms, an alkoxygroup having from 1 to 4 carbon atoms, a phenoxy group, a fluorine atom,a silyl group, an amino group, a cyano group and a group composed of acombination of these groups.

In the formula (I-1), Ry represents a hydrogen atom, an alkyl group, aperfluoroalkyl group or an aryl group. Ry is preferably a hydrogen atom,an alkyl group having from 1 to 5 carbon atoms or a phenyl group whichmay have the foregoing substituent T, and more preferably a hydrogenatom. Plural substituents Ts may be connected to each other.

In the formula (I-2), each of Ri¹ to Ri⁴ independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and adjacentsubstituents among Ri¹ to Ri⁴ may be connected to each other.

Ri¹ is preferably a hydrogen atom or an alkyl group, and more preferablya hydrogen atom.

Ri² is preferably a hydrogen atom, an alkyl group, an aryl group or aheterocyclic group; more preferably a hydrogen atom or an alkyl group;and further preferably a hydrogen atom.

Ri³ is preferably a hydrogen atom, an alkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a fluorine atom ora heterocyclic group; more preferably a hydrogen atom, an alkyl group,an aryl group or a fluorine atom; further preferably a hydrogen atom oran alkyl group; and especially preferably a hydrogen atom.

Ri⁴ is preferably a hydrogen atom, an alkyl group, an aryl group or aheterocyclic group; more preferably a hydrogen atom or an alkyl group;and further preferably a hydrogen atom.

In the formula (I-3), each of Ri⁵ to Ri¹² independently represents ahydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a diarylaminogroup, a cyano group, a fluorine atom, a trialkylsilyl group, atriarylsilyl group, an alkyldiarylsilyl group, a dialkylarylsilyl group,a heterocyclic group or a heterocyclic oxy group; and adjacentsubstituents among Ri⁵ to Ri⁸, adjacent substituents among Ri⁹ to Ri¹²,and Ri⁸ and Ri⁹ may be each connected to each other.

Ri⁵ is preferably a hydrogen atom or an alkyl group.

Ri⁶ is preferably a hydrogen atom, an alkyl group, an aryl group or aheterocyclic group; and more preferably a hydrogen atom or an alkylgroup.

Ri⁷ is preferably a hydrogen atom, an alkyl group, an aryl group, analkoxy group, an aryloxy group, a dialkylamino group, a fluorine atom ora heterocyclic group; more preferably a hydrogen atom, an alkyl group,an aryl group or a fluorine atom; further preferably a hydrogen atom oran alkyl group; and especially preferably a hydrogen atom.

Ri⁸ is preferably a hydrogen atom, an alkyl group, an aryl group or aheterocyclic group; more preferably a hydrogen atom or an alkyl group;and further preferably a hydrogen atom.

Ri⁹ is preferably a hydrogen atom, an alkyl group, an aryl group, aheterocyclic group or a fluorine atom; and more preferably a hydrogenatom, an alkyl group or a fluorine atom.

Ri¹⁰ is preferably a hydrogen atom, an alkyl group, an aryl group or aheterocyclic group; and more preferably a hydrogen atom, an alkyl groupor an aryl group.

Ri¹¹ is preferably a hydrogen atom, an alkyl group, an aryl group, aheterocyclic group or a fluorine atom; and more preferably a hydrogenatom, an alkyl group, an aryl group or a fluorine atom.

Ri¹² is preferably a hydrogen atom, an alkyl group, an aryl group or aheterocyclic group; and more preferably a hydrogen atom or an alkylgroup.

More preferred examples of the monoanionic bidentate ligand includeacetylacetonate (acac), picolinate (pic) and derivatives thereof. In theinvention, from the viewpoints of stability of the complex and highlight emission quantum yield, the monoanionic bidentate ligand ispreferably acetylacetonate.

In the foregoing formulae, the monoanionic bidentate ligand is bonded toiridium at the atom marked with “*”.

A preferred embodiment of the Ir complex represented by the formula(E-1) is an Ir complex material represented by the following formula(E-2).

Next, the formula (E-2) is described.

In the formula (E-2), each of A¹ to A⁸ independently represents anitrogen atom or C—R; R represents a hydrogen atom or a substituent; X—Yrepresents a monoanionic bidentate ligand; and n represents an integerof from 1 to 3.

Each of A¹ to A⁸ independently represents a nitrogen atom or C—R. Rrepresents a hydrogen atom or a substituent; and Rs may be connected toeach other to form a ring. As the substituent represented by R, thoseexemplified previously in the substituent group A can be applied. Rpreferably represents a hydrogen atom, an alkyl group, an aryl group, anaromatic heterocyclic group, a cyano group, a silyl group, an aminogroup or a fluorine atom. If possible, such a substituent can furtherhave a substituent, and as the substituent, those exemplified previouslyin the substituent group A can be applied. The substituent is preferablyan alkyl group, an aryl group, an aromatic heterocyclic group, a cyanogroup, a silyl group, an amino group or a fluorine atom.

Each of A¹ to A⁴ is preferably C—R. In the case where each of A¹ to A⁴is C—R, R of A³ is preferably a hydrogen atom, an alkyl group, an arylgroup, an amino group, a fluorine atom or a cyano group; more preferablya hydrogen atom, an amino group or a fluorine atom; and especiallypreferably a hydrogen atom or a fluorine atom.

In the case where each of A¹, A² and A⁴ is C—R, R is preferably ahydrogen atom, an alkyl group, an aryl group, an amino group, a fluorineatom or a cyano group; more preferably a hydrogen atom, an amino groupor a fluorine atom; and especially preferably a hydrogen atom.

Each of A⁵ to A⁸ independently represents C—R or a nitrogen atom. Rrepresents a hydrogen atom, an alkyl group, an aryl group, an aromaticheterocyclic group, a cyano group, a silyl group, an amino group or afluorine atom. If possible, such a substituent can further have asubstituent, and as the substituent, those exemplified previously in thesubstituent group A can be applied. The substituent is preferably analkyl group, an aryl group, an aromatic heterocyclic group, a cyanogroup, a silyl group, an amino group or a fluorine atom.

In the case where each of A⁵ to A⁸ is C—R, R is preferably a hydrogenatom, an alkyl group, a perfluoroalkyl group, an aryl group, an aromaticheterocyclic group, a dialkylamino group, a diarylamino group, a cyanogroup or a fluorine atom; more preferably a hydrogen atom, an alkylgroup, a perfluoroalkyl group, an aryl group, a dialkylamino group, acyano group or a fluorine atom; and further preferably a hydrogen atom,an alkyl group, a trifluoromethyl group or a fluorine atom. Also, ifpossible, the substituents may be connected to each other to form acondensed ring structure. In the case where the light emissionwavelength is shifted to the short wavelength side, it is preferablethat A⁶ is an N atom.

X—Y and n are synonymous with X—Y and n in the formula (E-1), andpreferred ranges thereof are also the same.

Another preferred embodiment of the Ir complex represented by theformula (E-1) is an iridium complex material represented by thefollowing formula (E-3).

Next, the formula (E-3) is described.

In the formula (E-3), each of A⁹ to A¹¹ and A¹³ to A¹⁶ independentlyrepresents C—R, N or N—R′; A¹² represents a carbon atom or a nitrogenatom; R represents a hydrogen atom or a substituent; R′ represents ahydrogen atom or a substituent; X—Y represents a monoanionic bidentateligand; and n represents an integer of from 1 to 3.

Each of A⁹ to A¹¹ and A¹³ to A¹⁶ independently represents C—R, N orN—R′. R preferably represents a hydrogen atom, an alkyl group, an arylgroup, an aromatic heterocyclic group, a cyano group, a silyl group, anamino group or a fluorine atom. R′ preferably represents a hydrogenatom, an alkyl group or an aryl group.

Each of A⁹ and A¹⁰ is preferably C—R. In the case where each of A⁹ andA¹⁰ is C—R, R of each of A⁹ and A¹⁰ is preferably a hydrogen atom, analkyl group, an aryl group, an amino group, an alkoxy group, an aryloxygroup, a fluorine atom or a cyano group; more preferably a hydrogenatom, an alkyl group, an aryl group, an amino group, a fluorine atom ora cyano group; further preferably a hydrogen atom, an amino group or afluorine atom; and especially preferably a hydrogen atom or a fluorineatom. If possible, such a substituent can further have a substituent. Asthe substituent, those exemplified previously in the substituent group Acan be applied. The substituent is preferably an alkyl group, an arylgroup, an aromatic heterocyclic group, a cyano group, a silyl group, anamino group or a fluorine atom.

A^(1l) is preferably N—R′, and R′ of A¹¹ is preferably an alkyl group oran aryl group. Plural Rs or R′s may be connected to each other to form aring.

X—Y and n are synonymous with X—Y and n in the formula (E-1), andpreferred ranges thereof are also the same.

The formula (E-3) is more preferably an iridium complex represented bythe following formula (E-4).

In the formula (E-4), each of R_(1a) to R, independently represents ahydrogen atom or a substituent; X—Y represents a monoanionic bidentateligand; and n represents an integer of from 1 to 3.

In the formula (E-4), each of R_(1a) to R_(1i) independently representsa hydrogen atom or a substituent. As the substituent, those exemplifiedpreviously in the substituent group A can be applied. Each of R_(1a) toR_(1i) is preferably a hydrogen atom, an alkyl group, an aryl group, anaromatic heterocyclic group, a cyano group, a silyl group, an aminogroup or a fluorine atom. If possible, such a substituent can furtherhave a substituent. As the substituent, those exemplified previously inthe substituent group A can be applied. The substituent is preferably analkyl group, an aryl group, an aromatic heterocyclic group, a cyanogroup, a silyl group, an amino group or a fluorine atom. In the casewhere each of R_(1a) to R_(1i) is bonded to the nitrogen atom, each ofR_(1a) to R_(1i) is not a hydrogen atom.

Each of R_(1a) to R_(1i) is preferably a hydrogen atom, an alkyl group,an aryl group, an amino group, a fluorine atom or a cyano group; morepreferably a hydrogen atom, an alkyl group, an aryl group, a fluorineatom or a cyano group; and especially preferably a hydrogen atom, analkyl group or an aryl group.

At least one of R_(1a) to R_(1i) is preferably an aryl group having adihedral angle against the mother structure of 70 degrees or more, morepreferably a substituent represented by the following formula ss-1, andfurther preferably a 2,6-disubstituted aryl group. It is the mostpreferable that R_(1b) is a 2,6-disubstituted aryl group.

In the formula ss-1, each of Ra, Rb and Rc independently represents anyone of a hydrogen atom, an alkyl group and an aryl group.

The alkyl group represented by each of Ra, Rb and Rc has preferably from1 to 30 carbon atoms, more preferably from 1 to 20 carbon atoms, andespecially preferably from 1 to 10 carbon atoms, and examples thereofinclude methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl,n-octyl, n-nonyl, n-decyl, n-dodecyl, n-octadecyl, n-hexadecyl,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl,1-adamantyl and trifluoromethyl. Of those, a methyl group and anisopropyl group are preferable.

The aryl group represented by each of Ra, Rb and Rc has preferably from6 to 30 carbon atoms, more preferably from 6 to 20 carbon atoms, andespecially preferably from 6 to 12 carbon atoms, and examples thereofinclude phenyl, o-methylphenyl, m-methylphenyl, p-methylphenyl,2,6-xylyl, p-cumenyl, mesityl, naphthyl and anthranyl. Of those, aphenyl group is preferable.

At least one of Ra and Rb is selected from an alkyl group or an arylgroup; it is preferable that at least one of Ra and Rb is selected froman alkyl group; it is more preferable that both Ra and Rb are an alkylgroup; and it is the most preferable that both Ra and Rb are a methylgroup or an isopropyl group.

The 2,6-disubstituted aryl group is preferably a 2,6-dimethylphenylgroup, a 2,4,6-trimethylphenyl group, a 2,6-diisopropylphenyl group, a2,4,6-triisopropylphenyl group, a 2,6-dimethyl-4-phenylphenyl group, a2,6-dimethyl-4-(2,6-dimethylpyridin-4-yl)phenyl group, a2,6-diphenylphenyl group, a 2,6-diphenyl-4-isopropylphenyl group, a2,4,6-triphenylphenyl group, a2,6-diisopropyl-4-(4-isopropylphenyl)phenyl group, a2,6-diisopropyl-4-(3,5-dimethylphenyl)phenyl group, a2,6-diisopropyl-4-(pyridin-4-yl)phenyl group or a2,6-di(3,5-dimethylphenyl)phenyl group.

On the other hand, it is preferable that at least one of R_(1a) to R_(h)is an alkyl group; and it is more preferable that R_(I), is an alkylgroup. The alkyl group is preferably an alkyl group branched at a sitefar from the benzyl position composed of 4 or more carbon atoms. Thealkyl group is preferably a methyl group or a neopentyl group, and morepreferably a neopentyl group.

On the other hand, it is preferable and at least one of R_(1a) andR_(1b) is an alkyl group.

On the other hand, R_(1a) is preferably an electron-donating group, andmore preferably a methyl group.

X—Y and n are synonymous with X—Y and n in the formula (E-1), andpreferred ranges thereof are also the same.

A still another preferred embodiment of the Ir complex represented bythe formula (E-1) is an iridium complex material represented by thefollowing formula (PQ-1).

The compound represented by the formula (PQ-1) is described.

In the formula (PQ-1), each of R₁ to R₁₀ independently represents ahydrogen atom, an alkyl group, an aryl group, an aromatic heterocyclicgroup, a cyano group, a silyl group, an amino group or a fluorine atom;R₁ to R₁₀ may be bonded to each other to form a ring, if possible;X^(P)—Y^(P) represents a monoanionic bidentate ligand represented by theforegoing formula (I-1), (I-2) or (I-3); and n represents an integer offrom 1 to 3.

Each of R₁ to R₁₀ independently represents a hydrogen atom, an alkylgroup, an aryl group, an amino group, a cyano group, an aromaticheterocyclic group, a silyl group or a fluorine atom; preferably ahydrogen atom, an alkyl group, an aryl group, an amino group, a cyanogroup, a silyl group or a fluorine atom; more preferably a hydrogenatom, an alkyl group or an aryl group; especially preferably a hydrogenatom, a methyl group, an ethyl group, an isopropyl group, a t-butylgroup, a neopentyl group, an isobutyl group, a phenyl group, a naphthylgroup, a phenanthryl group or a tolyl group; and most preferably ahydrogen atom, a methyl group or a phenyl group.

If possible, such a substituent can further have a substituent, and asthe substituent, those exemplified previously in the substituent group Acan be applied. The substituent is preferably an alkyl group, an arylgroup, an aromatic heterocyclic group, a cyano group, a silyl group, anamino group or a fluorine atom.

Also, if possible, these substituents may be bonded to each other toform a ring.

The ring which the substituents form each other is preferably a 5- to6-membered ring, and examples thereof include a benzene ring, a pyridinering, a pyrimidine ring, a pyrazine ring, an imidazole ring, a pyrazolering, an oxazole ring, a thiazole ring, a thiophene ring and a furanring. Of these, a benzene ring, a pyridine ring and a pyrazine ring aremore preferable; a benzene ring and a pyridine ring are furtherpreferable; and a benzene ring is especially preferable. The ring whichthe substituents form each other may further have a substituent, and asthe substituent, those exemplified previously in the substituent group Acan be applied. The substituent is preferably an alkyl group, aperfluoroalkyl group, an aryl group, an aromatic heterocyclic group, adialkylamino group, a diarylamino group, an alkoxy group, a cyano groupor a fluorine atom.

n is preferably from 2 to 3, and more preferably 2.

(X^(P)—Y^(P)) is synonymous with X—Y in the foregoing formula (E-1), anda preferred range thereof is also the same. It may be considered thatsuch a ligand does not directly contribute to light emittingcharacteristics but is able to control the light emittingcharacteristics of a molecule. Examples of such a monoanionic bidentateligand include ligands disclosed on pages 89 to 90 of Lamansky, et al.,WO 02/15645. Preferred examples of the monoanionic bidentate ligandinclude acetylacetonate (acac), picolinate (pic) and derivativesthereof.

(X^(P)—Y^(P)) is especially preferably a bidentate ligand represented bythe following formula L.

In the formula L, each of R^(L1) and R^(L2) independently represents analkyl group having from 1 to 5 carbon atoms or a phenyl group which mayhave a substituent selected from a substituent group T2. In theinvention, the substituent group T2 is defined as follows.

(Substituent Group T2)

An alkyl group having from 1 to 6 carbon atoms, an alkenyl group havingfrom 2 to 6 carbon atoms, a phenyl group, an aromatic heterocyclic grouphaving from 5 to 10 carbon atoms, an alkoxy group having from 1 to 4carbon atoms, a phenoxy group, a fluorine atom, a silyl group, an aminogroup, a cyano group and a group composed of a combination of thesegroups.

Plural substituents selected from the substituent group T2 may beconnected to each other to form an aromatic hydrocarbon ring; and themonoanionic bidentate ligand is bonded to iridium at the atom markedwith “*”.

Each of R^(L1) and R^(L2) is preferably a methyl group, an ethyl group,an n-propyl group, an isopropyl group, an n-butyl group, an isobutylgroup, a t-butyl group, a phenyl group, a tolyl group, an ethylphenylgroup, a biphenyl group or a naphthyl group; more preferably a methylgroup, an ethyl group, a t-butyl group or a phenyl group; and furtherpreferably a methyl group, a t-butyl group or a phenyl group.

Examples of the organometallic complex of the invention are enumeratedbelow, but it should not be construed that the invention is limitedthereto.

The phosphorescent metal complex containing the monoanionic bidentateligand represented by any one of the formulae (E-1) to (E-4) and iridiumcan be synthesized by various techniques such as methods disclosed in,for example, US2007/0190359 and US2008/0297033.

For example, the phosphorescent metal complex can be obtained by areaction of a ligand or a dissociated material thereof and a metalcompound in the absence or presence of a solvent (for example, halogenbased solvents, alcohol based solvents, ether based solvents, esterbased solvents, ketone based solvents, nitrile based solvents, amidebased solvents, sulfone based solvents, sulfoxide based solvents, water,etc.) and in the absence or presence of a base (various inorganic ororganic bases, for example, sodium methoxide, t-butoxypotassium,triethylamine, potassium carbonate, etc.) at a temperature of not higherthan room temperature or by heating (in addition to usual heating, aheating technique with a microwave is also effective).

Also, the compounds exemplified previously as the compound representedby the formula (PQ-1) can be synthesized by various methods such as amethod disclosed in, for example, U.S. Pat. No. 3,929,689. For example,Compound 4 can be synthesized using 2-phenylquinoline as a starting rawmaterial by a method disclosed at page 18, lines 2 to 13 of U.S. Pat.No. 3,929,689. Also, Compound 58 can be synthesized using2-(2-naphthyl)quinoline as a starting raw material by a method disclosedat page 18, line 14 to page 19, line 8 of U.S. Pat. No. 3,929,689.

The material for organic luminescence device of the invention can beused for the preparation of an organic electroluminescence device.

[Light emitting layer prepared using the material for organicelectroluminescence material having a water content before filmformation of 100 ppm or more and not more than 1,000 ppm]

The invention is also concerned with a light emitting layer preparedusing the foregoing material for organic electroluminescence materialhaving a water content before film formation of 100 ppm or more and notmore than 1,000 ppm. The light emitting layer of the invention can beused for an organic electroluminescence device.

In the light emitting layer of the invention, a preferred range of thematerial for organic electroluminescence device having a water contentbefore film formation of 100 ppm or more and not more than 1,000 ppm isone described previously, and it is preferable that the material fororganic electroluminescence device is the foregoing phosphorescentiridium complex.

It is preferable that the light emitting layer of the invention issubjected to film formation by further using at least one host materialin addition to the foregoing phosphorescent organometallic complex.Though the host material may be any of a hole transporting host materialor an electron transporting host material, it is preferably a bothcharge transporting host material.

From the viewpoint that an organic electroluminescence device withexcellent external quantum efficiency and driving durability, the hostmaterial is preferably a compound represented by the following formula(4-1) or (4-2).

The material represented by the formula (4-1) or (4-2) is described.

In the formulae (4-1) and (4-2), each of d and e represents an integerof from 0 to 3, and at least one of them is 1 or more; f represents aninteger of from 1 to 4; R′₈ represents a substituent; when plural R′₈sare present, each R′₈ may be the same as or different from every otherR′₈; and at least one of R′₈s represents a carbazole group representedby the following formula (5).

In the formula (5), each of R′₉s independently represents a substituent;and g represents an integer of from 0 to 8.

Each of R′₈s independently represents a substituent, and specifically,it is a halogen atom, an alkoxy group, a cyano group, a nitro group, analkyl group, an aryl group, a heterocyclic group or the substituentrepresented by the formula (5). In the case where R′₈ does not representthe formula (5), it is preferably an alkyl group having not more than 10carbon atoms or a substituted or unsubstituted aryl group having notmore than 10 carbon atoms, and more preferably an alkyl group having notmore than 6 carbon atoms.

Each of R′₉s independently represents a substituent, and specifically,it is a halogen atom, an alkoxy group, a cyano group, a nitro group, analkyl group, an aryl group or a heterocyclic group, preferably an alkylgroup having not more than 10 carbon atoms or a substituted orunsubstituted aryl group having not more than 10 carbon atoms, and morepreferably an alkyl group having not more than 6 carbon atoms.

g represents an integer of from 0 to 8; and from the viewpoint that thecarbazole structure bearing charge transport is not excessively blocked,g is preferably from 0 to 4. Also, from the viewpoint of easy synthesis,in the case where the carbazole has a substituent, it is preferable tohave a substituent such that it is symmetrical about the nitrogen atom.

In the formula (4-1), from the viewpoint of keeping charge transportcapability, the sum of d and e is preferably 2 or more. Also, it ispreferable that R′₈ is substituted at a meta-position against the otherbenzene ring. This is because in the ortho-substitution, a sterichindrance between the adjacent substituents to each other is large, andtherefore, the bond is easily cleaved, and the durability becomes low.Also, in the para-substitution, the molecular shape becomes close to arigid rod-like form, and crystallization is easy to take place, andtherefore, device deterioration is easy to take place under ahigh-temperature condition. Specifically, it is preferable that thecompound represented by the formula (4-1) is a compound represented bythe following structure.

In the foregoing formula, each of R′₉s independently represents asubstituent; and g represents an integer of from 0 to 8.

In the formula (4-2), from the viewpoint of keeping charge transportcapability, f is preferably 2 or more. In the case where f is 2 or 3,from the same viewpoint, it is preferable that R′₈s are substituted atthe meta-position each other. Specifically, it is preferable that thecompound represented by the formula (4-2) is a compound represented bythe following structure.

In the foregoing formula, each of R′₉s independently represents asubstituent; and g represents an integer of from 0 to 8.

In the case where each of the formulae (4-1) and (4-2) has a hydrogenatom, there is included an isotope of hydrogen (for example, a deuteriumatom, etc.). In that case, all of the hydrogen atoms in the compound maybe replaced by an isotope of hydrogen. Also, the compound represented byeach of the formulae (4-1) and (4-2) may be a mixture including acompound in which a part of the hydrogen atoms is an isotope ofhydrogen. The compound represented by each of the formulae (4-1) and(4-2) is preferably a compound in which R′₉ in the formula (5) issubstituted with deuterium, and the following structures are especiallypreferable.

Furthermore, it is expressed that atoms constituting each substituentinclude isotopes thereof.

It is possible to synthesize the compound represented by each of theformulae (4-1) and (4-2) by a combination of various known synthesismethods. Most generally, with respect to the carbazole compound, thereis exemplified a synthesis by the Aza-Cope rearrangement reaction of acondensate of an aryl hydrazine and a cyclohexane derivative andsubsequent dehydroaromatization (Reactions and Syntheses: In the OrganicChemistry, page 339, written by L. F. Tieze and Th. Eicher, translatedby Takano and Ogasawara and published by Nankodo). Also, with respect toa coupling reaction of the obtained carbazole compound and a halogenatedaryl compound using a palladium catalyst, there are exemplified themethods described in Tetrahedron Letters, Vol. 39, page 617 (1998),ibid., Vol. 39, page 2367 (1998) and ibid., Vol. 40, page 6393 (1999)and so on. The reaction temperature and the reaction time are notparticularly limited, and conditions described in the foregoingdocuments can be applied. Also, with respect to some compounds includingmCP, etc., commercially available compounds can be suitably used.

With respect to the compound represented by each of the formulae (4-1)and (4-2) according to the invention, though it is preferable to form athin layer by a vacuum vapor deposition process, a wet process such assolution coating can also be suitably adopted. From the viewpoints ofvapor deposition aptitude and solubility, a molecular weight of thecompound represented by each of the formulae (4-1) and (4-2) ispreferably not more than 2,000, more preferably not more than 1,200, andespecially preferably not more than 800. Also, from the viewpoint ofvapor deposition aptitude, when the molecular weight is too low, a vaporpressure is small, change from a gas phase to a solid phase does nottake place, and it is difficult to form an organic layer. Therefore, themolecular weight of the compound represented by each of the formulae(4-1) and (4-2) is preferably 250 or more, and especially preferably 300or more.

The compound represented by each of the formulae (4-1) and (4-2) is acompound having any one of the following structures or a compoundobtained by substituting one or more hydrogen atoms thereof with adeuterium atom.

In the foregoing formulae, each of R′₉s independently represents asubstituent.

Specific examples of the compound represented by each of the formulae(4-1) and (4-2) in the invention are enumerated below, but it should notbe construed that the invention is limited thereto.

A content of the phosphorescent organometallic complex in the lightemitting layer of the invention is preferably from 0.1 to 50% by mass,more preferably from 1 to 40% by mass, and most preferably from 5 to 30%by mass in the light emitting layer. (In this specification, mass ratiois equal to weight ratio.)

A content of the host material (preferably the compound represented bythe formula (4-1) or (4-2)) in the light emitting layer of the inventionis preferably from 30 to 95% by mass, more preferably from 40 to 95% bymass, further preferably from 50 to 95% by mass, and especiallypreferably from 70 to 95% by mass.

[Composition Containing the Material for Organic ElectroluminescenceDevice Having a Water Content Before Film Formation of 100 ppm or Moreand not More than 1,000 ppm]

The invention is also concerned with a composition containing theforegoing material for organic electroluminescence material having awater content before film formation of 100 ppm or more and not more than1,000 ppm.

A content of the material for organic electroluminescence device havinga water content before film formation of 100 ppm or more and not morethan 1,000 ppm in the composition of the invention is preferably from0.1 to 50% by mass, more preferably from 1 to 40% by mass, and mostpreferably from 5 to 30% by mass.

Other component which may be contained in the composition of theinvention may be an organic material or an inorganic material. As theorganic material, the host material represented by the formula (4-1) or(4-2), or materials which are exemplified later as other host material,a fluorescent material, a phosphorescent material and a hydrocarbonmaterial can be applied. Of these, a host material and a hydrocarbonmaterial are preferable; and the compound represented by the formula(4-1) or (4-2) is more preferable.

A content of the host material to be contained in the composition of theinvention is preferably from 30 to 95% by mass, more preferably from 40to 95% by mass, further preferably from 50 to 95% by mass, andespecially preferably from 70 to 95% by mass.

The composition of the invention can be formed into an organic layer ofthe organic electroluminescence device by a dry film formation methodsuch as a vapor deposition method and a sputtering method, a transfermethod, a printing method or the like.

(Organic Electroluminescence Device)

The device of the invention is described in detail.

The organic electroluminescence device of the invention is an organicelectroluminescence device comprising a substrate having thereon a pairof electrodes and at least one organic layer including a light emittinglayer between the electrodes, wherein the foregoing material for organicelectroluminescence device is used in the at least one organic layer.

In the organic electroluminescence device of the invention, the layerformed of the material for organic electroluminescence device having awater content before film formation of 100 ppm or more and not more than1,000 ppm is an organic layer, and preferably a light emitting layer,and furthermore, it may have plural organic layers.

In view of the nature of the luminescence device, it is preferable thatat least one electrode of an anode and a cathode is transparent ortranslucent.

FIG. 1 shows an example of a configuration of the organicelectroluminescence device according to the invention. In an organicelectroluminescence device 10 according to the invention shown in FIG.1, a light emitting layer 6 is interposed between an anode 3 and acathode 9 on a supporting substrate 2. Specifically, a hole injectionlayer 4, a hole transport layer 5, the light emitting layer 6, a holeblocking layer 7 and an electron transport layer 8 are laminated in thisorder between the anode 3 and the cathode 9.

<Configuration of Organic Layer>

The layer configuration of the organic layer is not particularly limitedand can be properly selected depending upon an application and a purposeof the organic electroluminescence device. However, it is preferablethat the organic layer is formed on the foregoing transparent electrodeor a back electrode. In that case, the organic layer is formed entirelyor partially on the foregoing transparent electrode or the foregoingback electrode.

The organic layer is not particularly limited with respect to its shape,size and thickness and so on and may be properly selected depending uponits purpose.

Specific examples of the layer configuration are exemplified below, butit should not be construed that the invention is limited to theseconfigurations.

-   -   Anode/hole transport layer/light emitting layer/electron        transport layer/cathode    -   Anode/hole transport layer/light emitting layer/second electron        transport layer (hole blocking layer)/first electron transport        layer/cathode    -   Anode/hole transport layer/light emitting layer/second electron        transport layer (hole blocking layer)/first electron transport        layer/electron injection layer/cathode    -   Anode/hole injection layer/hole transport layer/light emitting        layer/second electron transport layer (hole blocking        layer)/first electron transport layer/cathode    -   Anode/hole injection layer/hole transport layer/light emitting        layer/second electron transport layer (hole blocking        layer)/first electron transport layer/electron injection        layer/cathode    -   Anode/hole injection layer/first hole transport layer/second        hole transport layer (electron blocking layer)/light emitting        layer/second electron transport layer (hole blocking        layer)/first electron transport layer/electron injection        layer/cathode

The device configuration, substrate, cathode and anode of the organicelectroluminescence device are disclosed in detail in, for example,JP-A-2008-270736, and the matters disclosed in this patent document canbe applied to the invention.

<Substrate>

It is preferable that the substrate which is used in the invention is asubstrate which does not scatter or decay light emitted from the organiclayer. In the case of an organic material, it is preferable that theorganic material is excellent in heat resistance, dimensional stability,solvent resistance, electric insulating properties and processability.

<Anode>

In general, the anode may have a function as an electrode for feeding ahole into the organic layer. The anode is not particularly limited withrespect to its shape, structure and size and so on and can be properlyselected among known electrode materials depending upon an applicationand a purpose of the luminescence device. As described previously, theanode is usually provided as a transparent anode.

<Cathode>

In general, the cathode may have a function as an electrode forinjecting an electron into the organic layer. The cathode is notparticularly limited with respect to its shape, structure and size andso on and can be properly selected among known electrode materialsdepending upon an application and a purpose of the luminescence device.

With respect to the substrate, the anode and the cathode, the mattersdisclosed in paragraphs [0070] to [0089] of JP-A-2008-270736 can beapplied to the invention.

<Organic layer>

The organic layer in the invention is described.

(Formation of Organic Layer)

In the organic electroluminescence device of the invention, each of theorganic layers can be suitably formed by any of a dry film formationmethod such as a vapor deposition method and a sputtering method, atransfer method or a printing method or the like. As the film formationmethod, a vapor deposition method is preferable.

(Light Emitting Layer)

—Light Emitting Material—

It is preferable that the light emitting layer contains at least onelight emitting material.

The light emitting material in the invention is preferably the foregoingmaterial for organic electroluminescence device having a water contentbefore film formation of 100 ppm or more and not more than 1,000 ppm,and more preferably the compound represented by the foregoing formula(E-1). By using the material for organic electroluminescence devicehaving a water content before film formation of 100 ppm or more and notmore than 1,000 ppm, inclusion of fine dusts into the material to becaused due to electrification is prevented. As a result, attachment offine dusts into the device can be prevented; a rate of occurrence ofshort-circuit device can be reduced; and a yield of the organicelectroluminescence device can be enhanced. Also, occurrence ofcloudiness of the device can be suppressed, and storage stability can beenhanced.

In general, a content of the light emitting material in the lightemitting layer is preferably from 0.1% by mass to 50% by mass, morepreferably from 1 to 40% by mass, and most preferably from 5 to 30% bymass relative to the mass of all of the compounds capable of forming thelight emitting layer in the light emitting layer.

Though a thickness of the light emitting layer is not particularlylimited, in general, it is preferably from 2 nm to 500 nm. From theviewpoint of external quantum efficiency, the thickness of the lightemitting layer is more preferably from 3 nm to 200 nm, and furtherpreferably from 5 nm to 100 nm.

The light emitting material may be any of a fluorescent material or aphosphorescent material, and from the viewpoint that a device withhigher efficiency is obtainable, the light emitting material ispreferably a phosphorescent material, and more preferably anorganometallic complex type phosphorescent material represented by anyone of the foregoing (E-1) to (E-4) or the foregoing formula (PQ-1). Thelight emitting material may be made of a single kind or two or morekinds thereof.

·Fluorescent Material:

Examples of the fluorescent material which can be used in the inventioninclude compounds, for example, benzoxazole derivatives, benzimidazolederivatives, benzothiazole derivatives, styrylbenzene derivatives,polyphenyl derivatives, diphenylbutadiene derivatives,tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarinderivatives, condensed aromatic compounds, perinone derivatives,oxadiazole derivatives, oxazine derivatives, aldazine derivatives,pyralizine derivatives, cyclopentadiene derivatives, bisstyrylanthracenederivatives, quinacridone derivatives, pyrrolopyridine derivatives,thiadiazolopyridine derivatives, cyclopentadiene derivatives,styrylamine derivatives, diketopyrrolopyrrole derivatives, aromaticdimethylidine compounds, various complexes represented by complexes of8-quinolinol derivatives and complexes of pyrromethene derivatives,polymer compounds such as polythiophene, polyphenylene and polyphenylenevinylene, organic silane derivatives, etc.

·Phosphorescent Material:

Examples of the phosphorescent material which can be used in theinvention include phosphorescent compounds disclosed in patentdocuments, for example, U.S. Pat. No. 6,303,238B1, U.S. Pat. No.6,097,147, WO 00/57676, WO 00/70655, WO 01/08230, WO 01/39234A2, WO01/41512A1, WO 02/02714A2, WO 02/15645A1, WO 02/44189A1, WO 05/19373A2,JP-A-2001-247859, JP-A-2002-302671, JP-A-2002-117978, JP-A-2003-133074,JP-A-2002-235076, JP-A-2003-123982, JP-A-2002-170684, EP 1211257,JP-A-2002-226495, JP-A-2002-234894, JP-A-2001-247859, JP-A-2001-298470,JP-A-2002-173674, JP-A-2002-203678, JP-A-2002-203679, JP-A-2004-357791,JP-A-2006-256999, JP-A-2007-19462, JP-A-2007-84635, JP-A-2007-96259,etc. Above all, more preferred examples of the light emitting dopantinclude Ir complexes, Pt complexes, Cu complexes, Re complexes, Wcomplexes, Rh complexes, Ru complexes, Pd complexes, Os complexes, Eucomplexes, Tb complexes, Gd complexes, Dy complexes and Ce complexes. Inparticular, Ir complexes, Pt complexes and Re complexes are preferable;and Ir complexes, Pt complexes and Re complexes each of which containsat least one coordination mode of a metal-carbon bond, a metal-nitrogenbond, a metal-oxygen bond and a metal-sulfur bond are more preferable.Furthermore, from the viewpoints of luminous efficiency, drivingdurability, chromaticity, etc., Ir complexes, Pt complexes and Recomplexes each of which contains a tridentate or multidentate ligand areespecially preferable.

A content of the phosphorescent material is preferably in the range of0.1% by mass or more and not more than 50% by mass, more preferably inthe range of 1% by mass or more and not more than 40% by mass, and mostpreferably in the range of 5% by mass and not more than 30% by massrelative to the total mass of the light emitting layer.

A content of the phosphorescent material (the compound represented bythe formula (E-1) and/or the phosphorescent material to be jointly used)which can be used in the invention is preferably in the range of 0.1% bymass or more and not more than 50% by mass, more preferably in the rangeof 1% by mass or more and not more than 40% by mass, and most preferablyin the range of 5% by mass and not more than 30% by mass relative to thetotal mass of the light emitting layer. In particular, when the contentof the phosphorescent material is in the range of 5% by mass and notmore than 30% by mass relative to the total mass of the light emittinglayer, the chromaticity of light emission of the organicelectroluminescence device is small with respect to the dependency onthe addition concentration of the phosphorescent material.

In the organic electroluminescence device of the invention, it is themost preferable that at least one kind of the compound represented bythe formula (E-1) or the compound represented by the formula (PQ-1) iscontained in an amount of from 5 to 30% by mass relative to the totalmass of the light emitting layer.

—Host Material—

The light emitting layer in the device of the invention may beconstituted of only a light emitting material, or may be constituted ofa mixed layer of a host material and a light emitting material. It ispreferable that the host material is a charge transport material. Thehost material may be made of a single kind or two or more kinds thereof.For example, there is exemplified a configuration of a mixture of anelectron transporting host material and a hole transporting hostmaterial. Furthermore, a material which does not have chargetransporting properties and which does not undergo light emission may becontained in the light emitting layer. Though the compound representedby the formula (4-1) or (4-2) is preferable as the host material whichis used in the invention, the following compounds may be furthercontained as the host material. That is, there can be exemplifiedpyrrole, indole, carbazole, CBP (4,4′-di(9-carbazoyl)biphenyl)),azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole,imidazole, thiophene, polyarylalkanes, pyrazoline, pyrazolone,phenylenediamine, arylamines, amino-substituted chalcone,styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatictertiary amine compounds, styrylamine compounds, porphyrin basedcompounds, polysilane based compounds, poly(N-vinylcarbazole), anilinebased copolymers, thiophene oligomers, conductive high-molecular weightoligomers such as polythiophene, organic silanes, carbon films,pyridine, pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole,oxadiazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone,thiopyrane dioxide, carbodiimide, fluorenylidenemethane,distyrylpyrazine, fluorine-substituted aromatic compounds, heterocyclictetracarboxylic acid anhydrides such as naphthaleneperillene,phthalocyanine, metal complexes of an 8-quinolinol derivative, metalphthalocyanines, various metal complexes represented by metal complexescontaining benzoxazole or benzothiazole as a ligand and derivativesthereof (may have a substituent or a condensed ring).

In the light emitting layer in the invention, from the standpoints ofcolor purity, luminous efficiency and driving durability, it ispreferable that the lowest excited triplet energy (T₁ energy) of thehost material (also including the compound represented by the formula(4-1) or (4-2)) is higher than the T₁ energy of the foregoingphosphorescent material.

Also, though a content of the host compound in the invention is notparticularly limited, from the viewpoints of luminous efficiency anddriving voltage, it is preferably 15% by mass or more and not more than95% by mass relative to the mass of all of the compounds capable offorming the light emitting layer.

As the light emitting layer in the device of the invention, one using,as a host material, the compound represented by the formula (4-1) or(4-2) and, as a light emitting material, the material for organicelectroluminescent device having a water content before film formationof 100 ppm or more and not more than 1,000 ppm, and preferably thecompound represented by the formula (E-1) is preferable.

Also, the light emitting layer may be made of a single layer or multiplelayers of two or more layers. In the case where the light emitting layeris made of plural layers, the compound represented by the formula (4-1)or (4-2) and the material for organic electroluminescent device having awater content before film formation of 100 ppm or more and not more than1,000 ppm may be contained in the two or more light emitting layers.Also, the respective light emitting layers may undergo light emission ina different luminescent color from each other.

—Hole Injection Layer and Hole Transport Layer—

Each of the hole injection layer and the hole transport layer is a layerhaving a function of accepting a hole from the anode or the anode sideto transport it into the cathode side.

—Electron Injection Layer and Electron Transport Layer—

Each of the electron injection layer and the electron transport layer isa layer having a function of accepting an electron from the cathode orthe cathode side to transport it into the anode side.

With respect to the hole injection layer, the hole transport layer, theelectron injection layer and the electron transport layer, the mattersdisclosed in paragraphs [0165] to [0167] of JP-A-2008-270736 can beapplied to the invention.

—Hole Blocking Layer—

The hole blocking layer is a layer having a function of preventingpermeation of the hole having been transported from the anode side tothe light emitting layer into the cathode side from occurring. In theinvention, the hole blocking layer can be provided as an organic layeradjacent to the light emitting layer on the cathode side.

As an example of an organic compound constituting the hole blockinglayer, for example, those exemplified previously as the hole transportmaterial can be applied. Examples of the organic compound constitutingthe hole blocking layer include aluminum complexes such asaluminum(III)bis(2-methyl-8-quinolinato)-4-phenylphenolate (abbreviatedas “BAlq”); triazole derivatives; and phenanthroline derivatives such as2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (abbreviated as “BCP”).

A thickness of the hole blocking layer is preferably from 1 nm to 500nm, more preferably from 5 nm to 200 nm, and further preferably from 10nm to 100 nm

The hole blocking layer may be of a single-layered structure composed ofone or two or more kinds of the foregoing materials, or may be of amultilayered structure composed of a plurality of layers of the samecomposition as or a different composition from each other.

—Electron Blocking Layer—

The electron blocking layer is a layer having a function of preventingpermeation of an electron having been transported from the cathode sideto the light emitting layer into the anode side from occurring. In theinvention, the electron blocking layer can be provided as an organiclayer adjacent to the light emitting layer on the anode side.

As an example of an organic compound constituting the electron blockinglayer, for example, those exemplified previously as the hole transportmaterial can be applied.

A thickness of the electron blocking layer is preferably from 1 nm to500 nm, more preferably from 5 nm to 200 nm, and further more preferablyfrom 10 nm to 100 nm.

The electron blocking layer may be of a single-layered structurecomposed of one or two or more kinds of the foregoing materials, or maybe of a multilayered structure composed of a plurality of layers of thesame composition as or a different composition from each other.

<Protective Layer>

In the invention, the whole of the organic electroluminescence devicemay be protected by a protective layer.

With respect to the protective layer, the matters disclosed inparagraphs [0169] to [0170] of JP-A-2008-270736 can be applied to theinvention.

<Sealing Vessel>

In the device of the invention, the whole of the device may be sealedusing a sealing vessel.

With respect to the sealing vessel, the matters disclosed in paragraph[0171] of JP-A-2008-270736 can be applied to the invention.

[Film Formation Method]

In the invention, it is preferable that the light emitting layer issubjected to film formation by simultaneously heating the compoundrepresented by the formula (4-1) or (4-2) and the material for organicelectroluminescence device having a water content before film formationof 100 ppm or more and not more than 1,000 ppm, thereby achievingsublimation and vapor deposition.

During the film formation, it is preferable to mix the compoundrepresented by the formula (4-1) or (4-2) and the material for organicelectroluminescence device having a water content before film formationof 100 ppm or more and not more than 1,000 ppm, and the composition ofthe invention may be used. With respect to a content proportion of thecompound represented by the formula (4-1) or (4-2) and the material fororganic electroluminescence device having a water content before filmformation of 100 ppm or more and not more than 1,000 ppm, a ratio of thematerial for organic electroluminescence device having a water contentbefore film formation of 100 ppm or more and not more than 1,000 ppm tothe compound represented by the formula (4-1) or (4-2) is preferably inthe range of 0.1% by mass or more and not more than 50% by mass, morepreferably in the range of 1% by mass or more and not more than 40% bymass, and most preferably in the range of 5% by mass or more and notmore than 30% by mass.

A temperature of heating in the vapor deposition is preferably from 200°C. to 400° C., and more preferably from 250° C. to 320° C.

A time of heating in the vapor deposition is preferably 0.1 hours to 350hours, and more preferably from 0.1 hours to 150 hours.

According to the film formation method of the invention, there is anadvantage that a light emitting film which is high in efficiency anddurability and small in a color change at the time of high-temperaturedriving can be easily prepared.

[Driving]

According to the organic electroluminescence device of the invention,light emission can be obtained by impressing a voltage of direct current(optionally including an alternating current component) (usually from 2volts to 15 volts) or a current of direct current between the anode andthe cathode.

As to the driving method of the organic electroluminescence device ofthe invention, driving methods disclosed in JP-A-2-148687,JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234685,JP-A-8-241047, Japanese Patent No. 2784615 and U.S. Pat. Nos. 5,828,429and 6,023,308 can be applied.

In the luminescence device of the invention, a light collectingefficiency can be enhanced by various known ways and means. For example,it is possible to enhance the light collecting efficiency and to enhancethe external quantum efficiency by processing a surface shape of thesubstrate (for example, forming a fine uneven pattern), controlling arefractive index of each of the substrate, the ITO layer and the organiclayer, controlling a thickness of each of the substrate, the ITO layerand the organic layer, or the like.

The external quantum efficiency of the luminescence device of theinvention is preferably 5% or more and not more than 100%, morepreferably 10% or more and not more than 100%, further preferably 15% ormore and not more than 100%, and especially preferably 20% or more andnot more than 30%. With respect to the numerical value of the externalquantum efficiency, a maximum value of the external quantum efficiencyat the time of driving the device at 20° C., or a value of the externalquantum efficiency in the vicinity of from 100 to 2,000 cd/m² at thetime of driving the device at 20° C., can be employed.

The luminescence device of the invention may be of a so-called topemission mode for collecting light emission from the anode side.

The organic electroluminescence device in the invention may have aresonator structure. For example, the organic electroluminescence devicein the invention includes a transparent substrate having a multilayeredfilm mirror composed of plural laminated films having a differentrefractive index from each other, a transparent or translucentelectrode, a light emitting layer and a metal electrode superimposedthereon. The light emitted in the light emitting layer repeatsreflection between the multilayered film mirror and the metal electrodewhile making them function as a reflector and resonates.

In another preferred embodiment, each of a transparent or translucentelectrode and a metal electrode functions as a reflector on atransparent substrate, and the light emitted in the light emitting layerrepeats reflection therebetween and resonates.

In order to form a resonator structure, an optical path length which isdetermined from effective refractive indexes of the two reflectors and arefractive index and a thickness of each layer between the reflectors isregulated so as to have an optimal value for the purpose of obtaining adesired resonance wavelength. A calculation expression of the case ofthe first embodiment is disclosed in JP-A-9-180883. A calculationexpression of the case of the second embodiment is disclosed inJP-A-2004-127795.

The invention is also concerned with a method for manufacturing anorganic electroluminescence device using the foregoing material fororganic electroluminescence device. That is, the method is a method formanufacturing a device comprising using an organic material having awater content, as measured before film formation, of 100 ppm or more andnot more than 1,000 ppm as a material to be used for an organicelectroluminescence device.

The invention is also concerned with a method for reducing a rate ofoccurrence of short-circuit device using the foregoing material fororganic electroluminescence device. That is, the invention is a methodfor reducing a rate of occurrence of short-circuit device comprisingusing an organic material having a water content, as measured beforefilm formation, of 100 ppm or more and not more than 1,000 ppm as amaterial to be used for an organic electroluminescence device.

(Application of Luminescence Device of the Invention)

The luminescence device of the invention can be suitably utilized forlight emission apparatuses, pixels, display devices, displays,backlights, electro-photographs, illumination light sources, recordinglight sources, exposure light sources, read light sources, markers,signboards, interiors, optical communications and so on. In particular,the luminescence device of the invention is preferably used for deviceswhich are driven in a region with high brightness, such as illuminationapparatuses and display apparatuses.

Next, the light emission apparatus of the invention is described byreference to FIG. 2.

The light emission apparatus of the invention is one using the foregoingorganic electroluminescence device.

FIG. 2 is a sectional view diagrammatically showing an example of thelight emission apparatus of the invention.

A light emission apparatus 20 of FIG. 2 is configured to include atransparent substrate (supporting substrate) 2, an organicelectroluminescence device 10, a sealing vessel 16 and so on.

The organic electroluminescence device 10 is configured in such a mannerthat an anode (first electrode) 3, an organic layer 11 and a cathode(second electrode) 9 are laminated in this order on the substrate 2.Also, a protective layer 12 is laminated on the cathode 9, andfurthermore, the sealing vessel 16 is provided on the protective layer12 via an adhesive layer 14. In this respect, a part of each of theelectrodes 3 and 9, a partition, an insulating layer and the like areomitted.

Here, a photocurable adhesive or a thermosetting adhesive such as anepoxy resin can be used as the adhesive layer 14, and for example, athermosetting adhesive sheet can also be used.

The application of the light emission apparatus of the invention is notparticularly limited, and examples thereof include, in addition toillumination apparatuses, display apparatuses of television receiver,personal computer, mobile phone, electronic paper, etc.

Next, the illumination apparatus according to an embodiment of theinvention is described by reference to FIG. 3.

FIG. 3 is a sectional view diagrammatically showing an example of theillumination apparatus according to an embodiment of the invention.

As shown in FIG. 3, an illumination apparatus 40 according to anembodiment of the invention is provided with the foregoing organic ELdevice 10 and a light scattering member 30. More specifically, theillumination apparatus 40 is configured in such a manner that thesubstrate 2 of the organic EL device 10 and the light scattering member30 come into contact with each other.

The light scattering member 30 is not particularly limited so far as itis able to scatter light. In FIG. 3, the light scattering member 30works as a member having a fine particle 32 dispersed in a transparentsubstrate 31. As the transparent substrate 31, for example, a glasssubstrate can be suitably exemplified. As the fine particle 32, atransparent resin fine particle can be suitably exemplified. As each ofthe glass substrate and the transparent resin fine particle, those whichare known can be used. Such illumination apparatus 40 is an apparatuswhich when light emission from the organic electroluminescence device 10is made incident into a light incident surface 30A of the lightscattering member 30, scatters the incident light by the lightscattering member 30 and outputs the scattered light as illuminationlight from a light outgoing surface 30B.

EXAMPLES

The invention is more specifically described below by reference to thefollowing Examples, but it should not be construed that the scope of theinvention is limited to those Examples.

Examples 1 to 22

All of materials used for the preparation of a device were subjected tosublimation purification and confirmed to have a purity (absorptionintensity area ratio at 254 nm) of 99.9% or more by means ofhigh-performance liquid chromatography (TSKgel ODS-110Z, manufactured byTosoh Corporation).

An indium tin oxide (ITO) film-provided glass substrate having athickness of 0.5 mm and a size of 2.5 cm in square (manufactured byGEOMATEC Corporation, surface resistance: 10 Ω/□) was put in a washingvessel, ultrasonically washed in 2-propanol and then subjected to aUV-ozone treatment for 30 minutes. The following organic layers weresuccessively vapor deposited on this transparent anode (ITO film) bymeans of vacuum vapor deposition so as to have each of deviceconfigurations shown in Tables 1 to 22.

The devices described in each of Tables 1 to 22 had the same deviceconfiguration, except for changing a water content before film formationof a compound as an objective material, as measured by the followingmethod. The water content was regulated by the addition of water so asto have a value shown in each of Tables 1 to 22. For example, the “watercontent” in Table 1 is a value obtained by measuring a water content ofCompound 1 as the “objective material” before film formation by thefollowing method. A symbol “<” in the column of “Water content” in eachof Tables 1 to 22 means a sign of inequality, and for example, “<5 ppm”means that the water content of a compound as the “objective material”before film formation is less than 5 ppm.

For example, the terms “Device configuration: ITO/CuPc (10)/NPD(30)/CBP+8% Compound 1 (30)/BAlq (10)/Alq (30)/LiF (0.1)/A1 (100)” inTable 1 mean that CuPc (film thickness: 10 nm); NPD (film thickness: 30nm); a mixture of 8% by mass of Compound 1 and 92% by mass of CBP (filmthickness: 30 nm); BA1q (film thickness: 10 nm); Alq (film thickness: 30nm); LiF (film thickness: 0.1 nm); and Al (film thickness: 100 nm) werelaminated in this order on the ITO film.

The obtained laminate was placed in a nitrogen gas-purged glove boxwithout being exposed to the air and sealed using a stainless steel-madesealing can and an ultraviolet ray-curable adhesive (XNR5516HV,manufactured by Nagase-CHIBA Ltd.), thereby obtaining each of devicesshown in Tables 1 to 22.

(Water Content of Material for Organic Electroluminescence Device)

With respect to a material as the objective material, from 30 minutes to2 hours before putting into a vapor deposition machine, by using a KarlFischer trace moisture meter (CA-200, manufactured by MitsubishiChemical Analytech Co., Ltd.), the material was heated to 140° C. by awater vaporizer (VA-200, manufactured by Mitsubishi Chemical AnalytechCo., Ltd.), and vaporized moisture was sent to a titration cell with dryN₂ at a flow rate of 250 mL/min, thereby measuring a water content ofthe material for organic electroluminescence device.

A material as the objective material was preserved so as not to changein the water content from the measurement of the water content to beingput into a vapor deposition machine.

(Performance Evaluation of Organic Electroluminescence Device)

The performance of each of the obtained devices was evaluated.

<Device Evaluation>

(a) External Quantum Efficiency:

Each of the devices was subjected to light emission upon being impressedwith a direct current voltage using a source measure unit MODEL 2400,manufactured by Toyo Corporation. Its brightness was measured using abrightness meter BM-8, manufactured by Topcon Corporation. An emissionspectrum and a light emission wavelength were measured using a spectralanalyzer PMA-11, manufactured by Hamamatsu Photonics K.K. An externalquantum efficiency at a brightness in the vicinity of 1,000 cd/m² wascalculated based on the thus measured values according to the brightnessconversion method. The evaluation results are shown in each table whiledefining the case where a reduction value of efficiency was less than0.3% as “A”, the case where the efficiency was reduced by 0.3% or moreand less than 1.5% as “B” and the case where the efficiency was reducedby 1.5% or more “C”, respectively on the basis of a value of a deviceusing a material having a water content of not more than a detectionlimit (namely, Comparative Devices C1-1 to C22-1 shown in the uppermostrow in the respective tables).

(b) Driving Durability:

Each of the devices was continuously subjected to light emission uponbeing impressed with a direct current voltage such that the brightnesswas 1,000 cd/m². A time T required until the brightness reached 500cd/m² was evaluated. The evaluation results are shown in each tablewhile defining the case where a ratio of the time T to that of the basisdevice was higher than 95% “A”, the case where a ratio of the time T tothat of the basis device was higher than 90% and not more than 95% as“B” and the case where a ratio of the time T to that of the basis devicewas not higher than 90% as “C”, respectively on the basis of a value ofa device using a material having a water content of not more than adetection limit (namely, Comparative Devices C1-1 to C22-1 shown in theuppermost row in the respective tables).

(c) Driving Voltage:

A voltage when each of the devices was impressed with a direct currentvoltage such that the brightness was 1,000 cd/m² was evaluated as adriving voltage. The evaluation results are shown in each table whiledefining the case where an elevation value was 0 V or more and less than2 V as “A”, the case where an elevation value was 0.2 V or more and lessthan 0.5 V as “B” and the case where an elevation value was 0.5 V ormore as “C”, respectively on the basis of a value of a device using amaterial having a water content of not more than a detection limit(namely, Comparative Devices C1-1 to C22-1 shown in the uppermost row inthe respective tables).

(d) Number of Short-circuit Devices:

Fifty devices (5×10 times vapor deposition within the same chamber) wereprepared under the same condition, and each of the devices was impressedwith a direct current voltage of from 0 V to 20 V using a source measureunit MODEL 2400, manufactured by Toyo Corporation. On that occasion, thenumber of devices which caused a short circuit and became non-lightemitting was evaluated in terms of a percentage.

(e) Storage Stability (Presence or Absence of Cloudy Device by VisualInspection):

Each of the devices was stored in a thermostat at 50° C. for 30 days.The evaluation results are shown in each table while defining the casewhere one or more devices wherein cloudiness could be confirmed byvisual inspection were present as “B” and the case where any devicewherein cloudiness could be confirmed by visual inspection was notpresent as “A”, respectively.

TABLE 1 Example 1 Device configuration: ITO/CuPc (10)/NPD (30)/CBP + 8%Compound 1 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C1-1 <5ppm Basis Basis Basis 12%  B Comparison material: C1-2 54 ppm A A A 10% A Compound 1 C1-3 70 ppm A A A 10%  B C1-4 86 ppm A A A 12%  B C1-5 95ppm A A A 6% A 1-1 127 ppm A A A 4% A Invention 1-2 301 ppm A A A 2% A1-3 457 ppm A A A 2% A 1-4 756 ppm A A A 0% A C1-6 1050 ppm A A B 2% AComparison C1-7 1460 ppm A B C 6% A C1-8 2980 ppm B C C 14%  A

TABLE 2 Example 2 Device configuration: ITO/CuPc (10)/NPD (30)/CBP + 8%Compound 2 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C2-1 <5ppm Basis Basis Basis 10% B Comparison material: C2-2 30 ppm A A A 12% BCompound 2 C2-3 57 ppm A A A 12% B 2-1 103 ppm A A A  4% B Invention 2-2390 ppm A A A  0% A 2-3 695 ppm A A A  4% A 2-4 940 ppm A A A  2% A C2-41200 ppm A B C 10% A Comparison C2-5 1940 ppm A B C 16% A C2-6 2600 ppmA C C 12% A

TABLE 3 Example 3 Device configuration: ITO/CuPc (10)/NPD (30)/CBP + 8%Compound 12 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Numberof Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC3-1 <5 ppm Basis Basis Basis 10%  B Comparison material: C3-2 15 ppm AA A 10%  B Compound 12 C3-3 51 ppm A A A 8% B 3-1 104 ppm A A A 4% AInvention 3-2 260 ppm A A A 2% A 3-3 680 ppm A A A 2% A 3-4 900 ppm A AA 4% A C3-4 1200 ppm A C C 6% A Comparison C3-5 2500 ppm A C C 2% A C3-63100 ppm B C C 6% A

TABLE 4 Example 4 Device configuration: ITO/CuPc (10)/NPD (30)/CBP + 8%Compound 8 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C4-1 <5ppm Basis Basis Basis 18% B Comparison material: C4-2 10 ppm A A A 16% BCompound 8 C4-3 40 ppm A A A 16% B C4-4 68 ppm A A A 10% A C4-5 92 ppm AA A 12% B 4-1 115 ppm A A A  6% A Invention 4-2 360 ppm A A A  0% A 4-3870 ppm A A A  4% A C4-6 1050 ppm A B C  8% A Comparison C4-7 2000 ppm AB C  8% A C4-8 3500 ppm B C C 12% A

TABLE 5 Example 5 Device configuration: ITO/CuPc (10)/NPD (30)/mCP + 8%Compound 9 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C5-1 <5ppm Basis Basis Basis 12%  B Comparison material: C5-2 17 ppm A A A 10% B Compound 9 C5-3 80 ppm A A A 12%  B 5-1 110 ppm A A A 6% A Invention5-2 240 ppm A A A 4% A 5-3 595 ppm A A A 2% A 5-4 760 ppm A A A 2% AC5-4 1100 ppm A C C 2% A Comparison C5-5 1900 ppm C C C 6% A C5-6 2750ppm C C C 16%  A C5-7 3200 ppm C C C 14%  A

TABLE 6 Example 6 Device configuration: ITO/CuPc (10)/NPD (30)/BAlq + 8%Compound 3 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C6-1 <5ppm Basis Basis Basis 10%  B Comparison material: C6-2 35 ppm A A A 8% BCompound 3 C6-3 60 ppm A A A 8% B C6-4 84 ppm A A A 10%  A 6-1 150 ppm AA A 4% A Invention 6-2 480 ppm A B A 4% A 6-3 900 ppm A A A 4% A C6-51800 ppm B B C 6% A Comparison C6-6 2700 ppm C C C 4% A

TABLE 7 Example 7 Device configuration: ITO/CuPc (10)/NPD (30)/BAlq + 8%Compound 4 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C7-1 <5ppm Basis Basis Basis 8% B Comparison material: C7-2 10 ppm A A A 8% BCompound 4 C7-3 75 ppm A A A 10%  B 7-1 145 ppm A A A 2% A Invention 7-2360 ppm A A A 0% A 7-3 800 ppm A A A 2% A C7-4 1100 ppm A A B 4% AComparison C7-5 2200 ppm B B C 10%  A C7-6 4000 ppm B C C 8% A

TABLE 8 Example 8 Device configuration: ITO/CuPc (10)/NPD (30)/BAlq + 8%Compound 5 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C8-1 <5ppm Basis Basis Basis 10%  B Comparison material: C8-2 10 ppm A A A 8% BCompound 5 C8-3 65 ppm A A A 10%  B 8-1 245 ppm A A A 2% A Invention 8-2460 ppm A A A 0% A 8-3 830 ppm A A A 2% B C8-4 1200 ppm A A B 0% AComparison C8-5 2100 ppm B B C 10%  A C8-6 3700 ppm B C C 10%  A

TABLE 9 Example 9 Device configuration: ITO/CuPc (10)/NPD (30)/BAlq + 8%Compound 6 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Number ofWater Driving quantum Driving short-circuit Storage Device No. contentvoltage efficiency durability devices stability Remark Objective C9-1 <5ppm Basis Basis Basis 8% B Comparison material: C9-2 10 ppm A A A 8% BCompound 6 C9-3 45 ppm A A A 8% B 9-1 150 ppm A A A 2% A Invention 9-2380 ppm A A A 0% B 9-3 810 ppm A A A 0% A C9-4 1300 ppm A A B 6% AComparison C9-5 2700 ppm B B C 8% A C9-6 3300 ppm B C C 12%  A

TABLE 10 Example 10 Device configuration: ITO/CuPc (10)/NPD (30)/BAlq +8% Compound 7 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) External Numberof Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC10-1 <5 ppm Basis Basis Basis 12%  B Comparison material: C10-2 60 ppmA A A 10%  B Compound 7 C10-3 83 ppm A B A 10%  B 10-1 127 ppm A A A 4%A Invention 10-2 450 ppm A A A 4% A 10-3 950 ppm A A A 2% A C10-4 1600ppm B C C 4% A Comparison C10-5 2450 ppm B C C 6% A C10-6 3000 ppm B C C10%  A

TABLE 11 Example 11 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 10 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC11-1 <5 ppm Basis Basis Basis 8% B Comparison material: C11-2 14 ppm AA A 14%  B Compound 10 C11-3 46 ppm A A A 12%  B C11-4 87 ppm A A A 8% A11-1 130 ppm A A A 4% A Invention 11-2 420 ppm A A A 2% A 11-3 645 ppm AA A 2% A C11-5 1300 ppm A B C 6% A Comparison C11-6 2900 ppm A C C 10% A

TABLE 12 Example 12 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 11 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC12-1 <5 ppm Basis Basis Basis 8% B Comparison material: C12-2 16 ppm AA A 12%  B Compound 11 C12-3 60 ppm A A A 12%  B C12-4 84 ppm A A A 8% A12-1 110 ppm A A A 4% A Invention 12-2 520 ppm A A A 4% A 12-3 700 ppm AA A 2% A C12-5 1100 ppm A B C 6% A Comparison C12-6 1900 ppm A C C 12% A

TABLE 13 Example 13 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 51 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC13-1 <5 ppm Basis Basis Basis 6% B Comparison material: C13-2 40 ppm AA A 10%  B Compound 51 C13-3 50 ppm A A A 12%  B C13-4 96 ppm A A A 8% B13-1 120 ppm A A A 4% A Invention 13-2 430 ppm A A A 2% A 13-3 690 ppm AA A 2% A C13-5 1300 ppm A C C 6% A Comparison C13-6 1600 ppm A C C 10% B

TABLE 14 Example 14 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 94 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC14-1 <5 ppm Basis Basis Basis 10%  B Comparison material: C14-2 30 ppmA A A 10%  B Compound 94 C14-3 70 ppm A A A 12%  B C14-4 85 ppm A A A 8%B 14-1 110 ppm A A A 2% A Invention 14-2 530 ppm A A A 2% A 14-3 720 ppmA A A 2% A C14-5 1500 ppm A C C 8% A Comparison C14-6 2100 ppm A C C10%  B

TABLE 15 Example 15 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 95 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC15-1 <5 ppm Basis Basis Basis 8% B Comparison material: C15-2 20 ppm AA A 8% B Compound 95 C15-3 40 ppm A A A 12%  B C15-4 70 ppm A A A 10%  B15-1 140 ppm A A A 2% A Invention 15-2 690 ppm A A A 4% A 15-3 780 ppm AA A 2% A C15-5 1400 ppm A C C 10%  A Comparison C15-6 2000 ppm A C C12%  A

TABLE 16 Example 16 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 97 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC16-1 <5 ppm Basis Basis Basis 6% B Comparison material: C16-2 30 ppm AA A 8% B Compound 97 C16-3 60 ppm A A A 10%  B C16-4 70 ppm A A A 10%  B16-1 110 ppm A A A 2% A Invention 16-2 640 ppm A A A 2% A 16-3 720 ppm AA A 4% A C16-5 1100 ppm A C C 12%  A Comparison C16-6 2300 ppm A C C12%  A

TABLE 17 Example 17 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 98 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC17-1 <5 ppm Basis Basis Basis 6% B Comparison material: C17-2 50 ppm AA A 8% B Compound 98 C17-3 70 ppm A A A 8% B C17-4 80 ppm A A A 10%  B17-1 150 ppm A A A 2% A Invention 17-2 330 ppm A A A 4% A 17-3 590 ppm AA A 4% A C17-5 1600 ppm A C C 14%  A Comparison C17-6 3100 ppm A C C12%  A

TABLE 18 Example 18 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 99 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC18-1 <5 ppm Basis Basis Basis 6% B Comparison material: C18-2 20 ppm AA A 8% B Compound 99 C18-3 40 ppm A A A 6% B C18-4 60 ppm A A A 10%  B18-1 160 ppm A A A 2% A Invention 18-2 410 ppm A A A 2% A 18-3 750 ppm AA A 4% A C18-5 1900 ppm A C C 10%  A Comparison C18-6 2700 ppm C C C12%  A

TABLE 19 Example 19 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 100 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC19-1 <5 ppm Basis Basis Basis 6% B Comparison material: C19-2 10 ppm AA A 8% B Compound 100 C19-3 20 ppm A A A 6% B C19-4 50 ppm A A A 8% B19-1 260 ppm A A A 2% A Invention 19-2 350 ppm A A A 2% A 19-3 540 ppm AA A 4% A C19-5 1700 ppm A C C 10%  A Comparison C19-6 2100 ppm A C C12%  A

TABLE 20 Example 20 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 101 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC20-1 <5 ppm Basis Basis Basis 6% B Comparison material: C20-2 10 ppm AA A 8% B Compound 101 C20-3 20 ppm A A A 6% B C20-4 40 ppm A A A 4% B20-1 160 ppm A A A 2% A Invention 20-2 230 ppm A A A 2% A 20-3 660 ppm AA A 2% A C20-5 2100 ppm A C C 8% A Comparison C20-6 5100 ppm C C C 12% A

TABLE 21 Example 21 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 102 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC21-1 <5 ppm Basis Basis Basis 6% B Comparison material: C21-2 10 ppm AA A 12%  B Compound 102 C21-3 30 ppm A A A 6% B C21-4 60 ppm A A A 10% B 21-1 360 ppm A A A 2% A Invention 21-2 430 ppm A A A 2% A 21-3 650 ppmA A A 2% A C21-5 3300 ppm C C C 8% A Comparison C21-6 4700 ppm C C C10%  A

TABLE 22 Example 22 Device configuration: ITO/CuPc (10)/NPD (30)/mCBP +8% Compound 103 (30)/BAlq (10)/Alq (30)/LiF (0.1)/Al (100) ExternalNumber of Water Driving quantum Driving short-circuit Storage Device No.content voltage efficiency durability devices stability Remark ObjectiveC22-1 <5 ppm Basis Basis Basis 6% B Comparison material: C22-2 10 ppm AA A 12%  B Compound 103 C22-3 50 ppm A A A 10%  B C22-4 60 ppm A A A 8%B 22-1 260 ppm A A A 2% A Invention 22-2 480 ppm A A A 2% A 22-3 850 ppmA A A 2% A C22-5 4300 ppm C C C 10%  A Comparison C22-6 5700 ppm C C C10%  A

From the results of Table 1, a relation between a water content (ppm)(abscissa) of Compound 1 as the objective material of Example 1 and thenumber of short-circuit devices (%) in the devices obtained using thesubject material is shown in a graph of FIG. 4.

From the results of Tables 1 to 22, it is understood that by using thematerial having a water content before film formation of from 100 to1,000 ppm, the devices of the invention are excellent in externalquantum efficiency and driving durability and are able to reduce thenumber of short-circuit devices without dropping device characteristicsand to enhance yields, as compared with the devices of the ComparativeExamples. In particular, the devices of the Comparative Examples using amaterial having a water content before film formation of less than 100ppm are not preferable because the number of short-circuit devicesincreases. Also, it is understood that the devices of the ComparativeExamples using a material having a water content before film formationexceeding 1,000 ppm are inferior in external quantum efficiency anddriving durability to the devices of the invention. Also, it isunderstood that in the devices of the invention, cloudiness that may beestimated to be caused due to crystallization of a fine material can besuppressed so that a device with excellent storage stability can beprovided.

Also, the device of the invention is suitable for a light emissionapparatus, a display apparatus and an illumination apparatus.

Structures of the compounds used in the foregoing Examples andComparative Examples are shown below.

According to the material for organic electroluminescence device of theinvention, it is possible to obtain an organic electroluminescencedevice with excellent light emitting characteristics and to reduce thenumber of short-circuit devices, thereby enhancing the productivity.

The organic electroluminescence device of the invention is small inpower consumption, has a high external quantum efficiency and isexcellent in driving durability and storage durability.

This application is based on Japanese patent application Nos.2009-201159 filed on Aug. 31, 2009, 2009-223453 filed on Sep. 28, 2009,and 2010-100396 filed on Apr. 23, 2010, the entire content of which ishereby incorporated by reference, the same as if set forth at length.

What is claimed is:
 1. A material in a solid state, said material beingfor an organic electroluminescence device, comprising: an organometalliccompound that is to be provided for a dry film formation process of anyof at least one organic layer included in the electroluminescencedevice, wherein the material has a water content before the dry filmformation process, as measured by the Karl Fischer method, of 100 ppm ormore and not more than 1,000 ppm, wherein the organometallic compound isan iridium complex represented by the following formula (E-1):

in the formula (E-1), each of Z¹ and Z² independently represents acarbon atom; A represents an atomic group for forming a 6-memberedaromatic ring together with Z¹ and N; B represents an atomic group forforming a 6-membered aromatic ring together with Z² and C; though eachof a line connecting Z¹ and N, a line connecting Z¹ and the atomic groupA, a line connecting N and the atomic group A, a line connecting Z² andC, a line connecting Z² and the atomic group B and a line connecting Cand the atomic group B is expressed by a single line, each may be eithera single bond or a double bond irrespective of a bonding species; and nrepresents an integer of
 3. 2. The material according to claim 1,wherein the iridium complex represented by the formula (E-1) isrepresented by the following formula (E-2):

in the formula (E-2), each of A¹ to A⁸ independently represents anitrogen atom or C—R; R represents a hydrogen atom, an alkyl group, anaryl group, an aromatic heterocyclic group, a cyano group, a silylgroup, an amino group or a fluorine atom; and n represents an integer of3.
 3. The material according to claim 1, wherein the iridium complex isrepresented by the following formula (PQ-1):

in the formula (PQ-1), each of R₁ to R₁₀ independently represents ahydrogen atom, an alkyl group, an aryl group, an aromatic heterocyclicgroup, a cyano group, a silyl group, an amino group or a fluorine atom;R₁ to R₁₀ may be bonded to each other to form a ring, if possible; and nrepresents an integer of
 3. 4. A composition in a solid state that is tobe provided for a dry film formation process of any of at least oneorganic layer included in an electroluminescence device, comprising: thematerial of claim 1 and a compound represented by the following formula(4-1) or (4-2):

in the formulae (4-1) and (4-2), each of d and e independentlyrepresents an integer of from 0 to 3, and at least one of d and e is 1or more; f represents an integer of from 1 to 4; R′₈ represents an alkylgroup, an aryl group, a heteroaryl group, a fluorine atom, a cyanogroup, an alkoxy group, an aryloxy group, an amino group or a silylgroup, and when plural R′₈s are present, each R′₈ may be the same ordifferent from every other R′₈; and at least one of R′₈s represents agroup represented by the following formula (5):

in the formula (5), each of R′₉s independently represents an alkylgroup, an aryl group, a heteroaryl group, a fluorine atom, a cyanogroup, an alkoxy group, an aryloxy group, an amino group or a silylgroup; and g represents an integer of from 0 to
 8. 5. A method formanufacturing an organic electroluminescence device, comprising: forminga layer comprising the material for an organic electroluminescencedevice according to claim 1.